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WGU C170 Chapter 5 correctly answered 2022
access plan A set of instructions generated at application compilation time that is created and managed by a DBMS. The access plan predetermines how an ap... [Show More] plication's query will access the database at run time. algorithms A process or set of operations in a calculation. automatic query optimization A method by which a DBMS finds the most efficient access path for the execution of a query. B-tree index An ordered data structure organized as an upside-down tree. bitmap index An index that uses a bit array (0s and 1s) to represent the existence of a value or condition. buffer cache See data cache data cache A shared, reserved memory area that stores the most recently accessed data blocks in RAM. Also called buffer cache. data files A named physical storage space that stores a database's data. It can reside in a different directory on a hard disk or on one or more hard disks. All data in a database is stored in data files. A typical enterprise database is normally composed of several data files. A data file can contain rows from one or more tables. data sparsity A column distribution of values or the number of different values a column can have. database performance tuning A set of activities and procedures designed to reduce the response time of a database system—that is, to ensure that an end-user query is processed by the DBMS in the minimum amount of time. database statistics In query optimization, measurements about database objects, such as the number of rows in a table, number of disk blocks used, maximum and average row length, number of columns in each row, and number of distinct values in each column. Such statistics provide a snapshot of database characteristics. DBMS performance tuning Activities to ensure that clients' requests are addressed as quickly as possible while making optimum use of existing resources. dynamic query optimization The process of determining the SQL access strategy at run time, using the most up-to-date information about the database extents In a DBMS environment, refers to the ability of data files to expand in size automatically using predefined increments. file group See table space. hash index An index based on an ordered list of hash values. input/output (I/O) request A low-level data access operation that reads or writes data to and from computer devices. manual query optimization An operation mode that requires the end user or programmer to define the access path for the execution of a query. manual statistical generation mode A mode of generating statistical data access information for query optimization. In this mode, the DBA must periodically run a routine to generate the data access statistics—for example, running the RUNSTAT command in an IBM DB2 database. procedure cache See SQL cache. [Show Less]
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WGU C170 Chapter 1 question & answers 100% correct
AREA In DB2, a named section of permanent storage space that is reserved to store the database. associative entity See composite entity. ... [Show More] bridge entity See composite entity. candidate key A minimal superkey; that is, a key that does not contain a subset of attributes that is itself a superkey. See key. closure A property of relational operators that permits the use of relational algebra operators on existing tables (relations) to produce new relations. composite entity An entity designed to transform an M:N relationship into two 1:M relationships. The composite entity's primary key comprises at least the primary keys of the entities that it connects. Also known as a bridge entity or associative entity. See also linking table. composite key A multiple-attribute key. dependent An attribute whose value is determined by another attribute. determination The role of a key. In the context of a database table, the statement "A determines B" indicates that knowing the value of attribute A means that the value of attribute B can be looked up. DIFFERENCE In relational algebra, an operator used to yield all rows from one table that are not found in another union-compatible table. DIVIDE In relational algebra, an operator that answers queries about one set of data being associated with all values of data in another set of data. domain In data modeling, the construct used to organize and describe an attribute's set of possible values. entity integrity The property of a relational table that guarantees each entity has a unique value in a primary key and that the key has no null values. equijoin A join operator that links tables based on an equality condition that compares specified columns of the tables. flags Special codes implemented by designers to trigger a required response, alert end users to specified conditions, or encode values. Flags may be used to prevent nulls by bringing attention to the absence of a value in a table. foreign key (FK) An attribute or attributes in one table whose values must match the primary key in another table or whose values must be null. See key. full functional dependence A condition in which an attribute is functionally dependent on a composite key but not on any subset of the key. functional dependence Within a relation R, an attribute B is functionally dependent on an attribute A if and only if a given value of attribute A determines exactly one value of attribute B. The relationship "B is dependent on A" is equivalent to "A determines B," and is written as A B. homonyms The use of the same name to label different attributes. Homonyms generally should be avoided. Some relational software automatically checks for homonyms and either alerts the user to their existence or automatically makes the appropriate adjustments. See also synonym. index An ordered array of index key values and row ID values (pointers). Indexes are generally used to speed up and facilitate data retrieval. Also known as an index key. index key See index. inner join A join operation in which only rows that meet a given criterion are selected. The join criterion can be an equality condition (natural join or equijoin) or an inequality condition (theta join). The inner join is the most commonly used type of join. Contrast with outer join. INTERSECT In relational algebra, an operator used to yield only the rows that are common to two union-compatible tables. JOIN In relational algebra, a type of operator used to yield rows from two tables based on criteria. There are many types of joins, such as natural join, theta join, equijoin, and outer join. join columns Columns that are used in the criteria of join operations. The join columns generally share similar values (have a compatible domain). key One or more attributes that determine other attributes. See also superkey, candidate key, primary key (PK), secondary key, and foreign key. key attribute The attributes that form a primary key. See also prime attribute. left outer join In a pair of tables to be joined, a join that yields all the rows in the left table, including those that have no matching values in the other table. For example, a left outer join of CUSTOMER with AGENT will yield all of the CUSTOMER rows, including the ones that do not have a matching AGENT row. See also outer join and right outer join. linking table In the relational model, a table that implements an M:M relationship. See also composite entity. natural join A relational operation that yields a new table composed of only the rows with common values in their common attribute(s). null The absence of an attribute value. Note that a null is not a blank. outer join A relational algebra join operation that produces a table in which all unmatched pairs are retained; unmatched values in the related table are left null. Contrast with inner join. See also left outer join and right outer join. predicate logic Used extensively in mathematics to provide a framework in which an assertion (statement of fact) can be verified as either true or false. primary key (PK) In the relational model, an identifier composed of one or more attributes that uniquely identifies a row. Also, a candidate key selected as a unique entity identifier. See also key. prime attribute A key attribute; that is, an attribute that is part of a key or is the whole key. See also key attributes. PRODUCT In relational algebra, an operator used to yield all possible pairs of rows from two tables. Also known as the Cartesian product. [Show Less]
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WGU C170 Terms correctly answered 2022
Associative Entity All relationships for the (...) entity should be many. Attribute An (...) is a property or characteristic of an entity. ... [Show More] Binary relationship A (...) is a relationship between two entity types. Cardinality (...) represents the maximum number of entities that can be involved in a particular relationship. Cascade Delete Will delete all records that reference the primary key Database A (...) is a collection of information that is organized so that it can easily be accessed, managed, and updated. E-R model An (...) is a data model for describing a database in an abstract way. Entity An (...) is an object or event in our environment that we want to keep track of. Intersection Data Associated with the concatenation of two segments Modality (...) represents the minimum number of entity occurrences that can be involved in a relationship. Ternary Relationship A (...) relationship is when three entities participate in the relationship. Unary Relationships (...) relationships associate occurrences of an entity type with other occurrences of the same entity type. Unique Identifier A (...) is any identifier which is guaranteed to be unique among all identifiers used for those objects and for a specific purpose. Data encryption When data is (...), it is changed, bit by bit or character by character, into a form that looks totally garbled. It can and must be reconverted, or decrypted, back to its original form to be of use. Data normalization Is a methodology for organizing attributes into tables so that redundancy among the non-key attributes is eliminated. Data volatility Describes how often stored data is updated. Data Volume Assessment Understanding of how much data will be in a database or a table within a database Denormalization The act of duplicating data in a database for performance or the preservation of historical information Disaster recovery Involves rebuilding an entire information system or significant parts of one after a catastrophic natural disaster such as a hurricane, tornado, earthquake, building collapse, or even a major fire Index Used to help a DBMS find data quickly Logical view Is a mapping onto a physical table or tables that allows an end user to access only a specified portion of data. Response time Is the delay from the time that the Enter Key is pressed to execute a query until the result appears on screen. Throughput Is the measure of how many queries fro [Show Less]
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Data Management Applications WGU C170 100%correct answers
What is a table? A table is a persistent representation of a logical relation that is a relation whose contents can be saved for permanent use. Wha... [Show More] t are the characteristics of a relational table? The characteristics of a relational table are that a table is perceived as a two-dimensional structure composed of rows and columns, each row (tuple) represents a single entity occurrence within the set, each column represents an attribute, each column has a distinct name, each intersection of a row and column represents a single data value, all values in a column must be of the same data format, the order of the rows and columns don't matter to the DBMS, and each table must have an attribute (or combination of attributes) that uniquely identifies each row (tuple). What is a tuple? A tuple is a row that represents a single entity occurrence within a set. What are records? A record is the same as a tuple (row). What is a field? A field is a column. What is a key? A key consists of one or more attributes that determine other attributes. For example, a social security number identifies all of the other attributes related to that person. What is determination? Determination is the state in which knowing the value of one attribute allows you to determine the value of another attribute. For example, if you know a key, you can find other information. What is functional dependence? Functional dependence is when knowing the value of one or more attributes lets you know the value of the other attributes. For example, knowing the first name and the social security number would let you find the person's last name. What is full functional dependence? Full functional dependence is when knowing the value of one or more attributes lets you know the value of other attributes and the value of the known attributes are NEEDED to find the other attributes. For example, a social security number lets you find the first and last name of someone. This is full functional dependence. If it was a social security number and a first name this would just be functional dependence because the first name is not required to look up the last name. All you need is the SSN. What is a determinant? A determinant is an attribute whose value determines the value of other attributes. For example, a social security number could be the determinant for your last name. What is a dependent? A dependent is an attribute whose value is determined by another attribute. For example, you last name could be a dependent of your social security number. What is a composite key? A composite key is a key that is composed of one or more attribute. For example, the key of your last name and you social security number could be used to determine your first name. This would be a composite key because you are using your last name and your SSN in the key. What is a superkey? A superkey is a key that can uniquely identify any row in a table. Some examples of this would be your social security number identifying a row corresponding to your information, but a superkey isn't limited to full functional dependence. Your SSN and your last name used as a key would still be a superkey. What is a candidate key? A candidate key is a minimal super key. This is to say it has no extra attributes. If you only need a social security number to identify the row related to a person than the candidate key is the SSN. A key consisting of an SSN and the last name in this case would not be a candidate key. What is entity integrity? Entity integrity is the condition in which each row (entity instance or tuple) in the table has it's own unique identity. This requires that all values in the primary key be unique and that the primary key cannot be null. What is a null? A null is the absence of a data value. A null should be avoided whenever possible. In fact, you can set a rule that prevents an attribute from being null. A null can create an issue when a function like average is used. What is a foreign key? A foreign key is the primary key of one table that has been placed into another table to create a common attribute. For instance, a student id number could be the primary key for information on a student but a foreign key for a table containing a class roster. What is referential integrity? Referential integrity is the condition in which every reference to an entity instance by another entity is valid. In other words, a foreign key needs to be either null or a valid primary key in another table. What is a primary key? A primary key is a candidate key selected to uniquely identify all other attributes in a given row and it may not contain null entries. Examples of this include student ID's and social security numbers. What is a secondary key? A secondary key is a key that is used strictly for data retrieval purposes. A secondary key does not always return a unique outcome. For instance, if a person doesn't know their student ID, you could still look them up by their first and last name in the system but that might return several students with the same name and you'd have to look through the list to find the appropriate one. What is a flag? A flag is used to indicate the absence of some value to avoid using a null. What is relational algebra? Relational algebra defines the theoretical way of manipulating table contents using relational operators. What is a relvar? A relvar is the variable that holds a relation. It is composed of two parts: a relvar heading and a relvar body. What is a relvar heading? The relvar heading contains the name of the attributes. What is a relvar body? A relvar body contains the relation. What is a relation (not in general terms where you can use table and relation interchangeably)? A relation is the data that we see in our tables not the data itself. It's a relationship between sets of information. What is the property of closure? Closure is a property that permits the use of relational operators on existing relations to create new relations. What is a unary operator? A unary operator in regards to SQL is an operator that works on only one table. What is the SELECT (sometimes referred to as RESTRICT) operator used for? The SELECT (or RESTRICT) operator is used to select certain rows (aka tuples). It yields values for all rows that satisfy a given condition. For example a SELECT statement that looks for students with a gpa below 2.0 could be used to produce a table with all rows that contain a gpa lower than 2.0. Formally, SELECT is denoted by a lower case sigma symbol. This is a unary operator that is it only accepts one table as input. What is the PROJECT operator used for? The PROJECT operator is a unary operator that will return only the attributes requested that is to say it yields columns. It does not limit the rows returned so it will return all rows within the requested columns. Formally it is denoted by the Greek letter pi. What is the UNION operator? The UNION operator combines all rows from two tables excluding duplicate rows. To be used in the UNION the two tables must contain the same attributes. Union is denoted by a symbol that looks like an uppercase U. What does it mean to be union-compatible? Union-compatible means that two or more tables contain the same number of columns of the same type. What is an INTERSECTION operator? An INTERSECTION operator is an operator that yields only rows that are in both tables. This operator requires that the tables be union-compatible. The symbol for this operation is similar to an upside down U. What is the DIFFERENCE operator? The DIFFERENCE operator is an operator that yields all the rows in one table that are not found in another table. It is seen as subtraction and it denoted by the minus sign -. It's important to note that given tables A and B the DIFFERENCE between A and B is not the same as the DIFFERENCE between B and A. Oder matters. What is the PRODUCT operator? The PRODUCT operator is an operator the yields the Cartesian product of two tables that is it yields all possible pairs of rows of the two tables. So, if one table has 3 rows and another table has 6 rows the PRODUCT of these two tables will result in a table containing 3 x 6 rows which equals 18 rows. It is represented by the multiplication symbol. What is the JOIN operator? The JOIN operator allows information from two tables to be intelligently combined into one table. It is the real power behind relational databases and allows for the use of independent tables linked by common attributes. What is a natural join? A natural join links tables by selecting only rows with common values in their common attributes. It is the result of a three stage process. First, it takes the PRODUCT of two tables thereby yielding all possible pairs of rows. Then it takes the SELECT that produces a table that contains rows such that the value of a certain attribute that are equal. Finally, it performs the PROJECT operator to ensure that there are no duplicate columns. An example of this would be if you had two tables contain student ID numbers that you wanted joined. It would first perform a Product producing a large table with all common rows. Then it would SELECT the rows in which the value of the student ids that occur in the same row are equal. Then it uses the PROJECT to eliminate the duplicate columns which in this case at the very least would get rid of one of the student id columns. What is an equijoin? Equijoin is a join operation that is performed in two steps. The first step takes the PRODUCT of two tables yielding all possible pairs of rows. Then it SELECTS rows that such that the values of a joined attribute are equal. In fact, this result is the second step of the natural join operation. This means that duplicate columns are not removed so you see the two values that are equal in the same row. What is a thetajoin? A thetajoin is any join operator that uses an ineqality comparison for the join attribute. So, it would make use of less than, greater than, less than or equal to, and greater than or equal to operators in the join statement. It works using the same two steps as the equijoin. What is an inner join? An inner join produces a table that has matched records. Natural joins and equijoins are good examples of this. What is an outer join? An outer join is a join where the matched pairs would be retained, and any unmatched values in the other table would be left null. What is a left outer join? This is an outer join where the first table of the join keeps the unmatched values and the second table has the values that are set to null. What is a right outer join? This is an outer join where the second table of the join keeps the unmatched values and the second table has the values set to null. What are outer joins particularly useful for? Outer joins are a great way to ensure referential integrity. This is especially true when adding tables that aren't from a database into a database. It's a good way to check for foreign key matches. What is the DIVIDE operator? The DIVIDE operator is an operator that is used to answer questions about one set of data being associated with all values of data in another set of data. For example, if you have a table that shows a list of product numbers associated with customer numbers indicating which customers purchased which products, and you have a second table which contains a list of products offered and you want to find out which customers purchased every product, you would DIVIDE the first table by the second table. What is a data dictionary? A data dictionary provides a detailed description of all tables in the database created by the user and the designer. It contains a minimum of all the attribute names and characteristics for each table of the system. Basically it contains metadata that is data about data. It doesn't contain the data itself, but it does contain the names and characteristics of said data. [Show Less]
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WGU C170 - Data Management – Applications Correctly answered 2022
Domain In data modeling, the construct used to organize and describe an attribute's set of possible values. Primary key (PK) An identifier composed ... [Show More] of one or more attributes that uniquely identifies a row. Also, a candidate key selected as a unique entity identifier. A minimal superkey. Key One or more attributes that determine other attributes. Determination The role of a key. In the context of a database table, the statement "A determines B" indicates that knowing the value of attribute A means that the value of attribute B can be looked up. Determinant Any attribute in a specific row whose value directly determines other values in that row. Dependent An attribute whose value is determined by another attribute. Full functional dependence A condition in which an attribute is functionally dependent on a composite key but not on any subset of the key. Composite key A multiple-attribute key. Key attributes The attributes that form a primary key Superkey An attribute or attributes that uniquely identify each entity in a table. Candidate key A minimal superkey; that is, a key that does not contain a subset of attributes that is itself a superkey. Entity integrity The property of a relational table that guarantees each entity has a unique value in a primary key and that the key has no null values. Null The absence of an attribute value. Foreign key An attribute or attributes in one table whose values must match the primary key in another table or whose values must be null. Referential integrity A condition by which a dependent table's foreign key must have either a null entry or a matching entry in the related table. Secondary key A key used strictly for data retrieval purposes. For example, the combination of last name, first name, middle initial, and telephone number will probably match the appropriate table row. Also called an alternate key. Relational algebra A set of mathematical principles that form the basis for manipulating relational table contents; the eight main functions are SELECT, PROJECT, JOIN, INTERSECT, UNION, DIFFERENCE, PRODUCT, and DIVIDE. Relvar Short for relation variable, a variable that holds a relation. It is a container (variable) for holding relation data, not the relation itself. Closure A property of relational operators that permits the use of relational algebra operators on existing tables (relations) to produce new relations. SELECT operator An operator used to select a subset of rows. Also known as RESTRICT. σ cus_code = 10010 PROJECT operator An operator used to select a subset of columns. In other words, it yields a vertical subset of a table. This operation retrieves all rows and some attributes of a table without using a WHERE clause to limit which rows of the table are included. π cus_fname, cus_lname UNION operator This set operator combines the result set of two or more SELECT statements, dropping the duplicate rows. supplier ∪ vendor Union-compatible Two or more tables that have the same number of columns and the corresponding columns have compatible domains. INTERSECT operator This set operator combines the output of two SELECT queries and returns only the rows that appear in both. supplier ∩ vendor DIFFERENCE An operator used to yield all rows from one table that are not found in another union-compatible table. supplier – vendor PRODUCT An operator used to yield all possible pairs of rows from two tables. customer × agent JOIN In relational algebra, a type of operator used to yield rows from two tables based on criteria. There are many types, such as natural, theta, equi, and outer. Natural join (JOIN) A relational operation that yields a new table composed of only the rows with common values in their common attribute(s). customer ⨝ agent Equijoin A join operator that links tables based on an equality condition that compares specified columns of the tables. Is a special type of theta join Theta join A join operator that links tables using an inequality comparison operator (<, >, <=, >=) in the join condition. INNER JOIN A join operation in which only rows that meet a given criterion are selected. The join criterion can be an equality condition (natural join or equijoin) or an inequality condition (theta join). This join is the most commonly used type of join. OUTER JOIN This join Returns a set of records that includes rows for which no corresponding match is found in the other table. Unmatched values in the related table are left null. Three types LEFT, RIGHT and FULL LEFT OUTER JOIN In a pair of tables to be joined, a join that yields all rows in the left table, including those that have no matching values in the other table. SELECT *FROM T1 ____________ T2 ON T1.C1=T2.C1 RIGHT OUTER JOIN In a pair of tables to be joined, a join that yields all of the rows in the right table, including the ones with no matching values in the other table. SELECT *FROM T1 ____________ T2 ON T1.C1=T2.C1 FULL OUTER JOIN Returns rows with matching values and includes all rows from both tables (T1 and T2) with unmatched values SELECT *FROM T1 ____________ T2 ON T1.C1=T2.C1 DIVIDE operator An operator that answers queries about one set of data being associated with all values of data in another set of data. It uses one 2-column table as the dividend and one single-column table as the divisor. JOIN operation This operation integrates data from two or more tables or combines them. It can be implemented in the FROM and WHERE clauses. Data dictionary A DBMS component that stores metadata. It contains the data definition as well as their characteristics and relationships. It may also include data that are external to the DBMS. Also known as an information resource dictionary System catalog A detailed system data dictionary that describes all objects in a database. Homonyms The use of the same name to label different attributes. Some relational software automatically check for these and either alerts the user to their existence or automatically makes the appropriate adjustments. Synonym The use of different names to identify the same object, such as an entity, an attribute, or a relationship; For example, car and auto refer to the same object The 1:M Relationship This relationship is the relational modeling ideal. One record in a table can be associated with one or more records in another table. For example, each customer can have many sales orders. The 1:1 Relationship This relationship should be rare in any relational database design. One entity can be related to only one other entity, and vice versa. The M:N Relationship This relationship cannot be implemented as such in the relational model however, it can be implemented by creating a new entity in 1:M relationships with the original entities. Composite entity An entity designed to transform an M:N relationship into two 1:M relationships. The entity's primary key comprises at least the primary keys of the entities that it connects. Also known as a bridge entity or associative entity. Linking table In the relational model, a table that implements a composite entity in a M:M relationship Cardinality Denotes how many instances of one object are related to instances of another object (maximum). Modality Denotes an instance of a specific entity is optional or mandatory in a relationship (minimum). Unary one-to-one A relationship between a single occurrence of an entity type with another single occurrence of the same entity type Unary one-to-many A relationship between a single occurrence of an entity type with any number of occurrences (minimum one) of the same entity type. Unary many-to-many A relationship between any occurrence of an entity type with any number of occurrences (minimum one) of the same entity type. Index An ordered array of key values and row ID values (pointers). They are generally used to speed up and facilitate data retrieval. Unique index An index in which the index key can have only one associated pointer value (row). Flags Special codes implemented by designers to trigger a required response, alert end users to specified conditions, or encode values. May be used to prevent nulls by bringing attention to the absence of a value in a table. Prime attribute An attribute that is part of a key or is the whole key. Set theory A part of mathematical science that deals with sets, or groups of things, and is used as the basis for data manipulation in the relational model. Required attribute In ER modeling, an attribute that must have a value. In other words, it cannot be left empty. Optional attribute In ER modeling, an attribute that does not require a value; therefore, it can be left empty. Identifiers The ERM uses one or more attributes that uniquely identify each entity instance. Relational schema The organization of a relational database as described by the database administrator. Composite identifier In ER modeling, a key composed of more than one attribute. Composite attribute An attribute that can be further subdivided to yield additional attributes. For example, a phone number such as 615-898- 2368 may be divided into an area code (615), an exchange number (898), and a four-digit code (2368). Compare to simple attribute. Single-valued attribute An attribute that can have only one value. Multivalued attribute An attribute that can have many values for a single entity occurrence. For example, an EMP_DEGREE attribute might store the string "BBA, MBA, PHD" to indicate three different degrees held. Derived attribute An attribute that does not physically exist within the entity and is computed via an algorithm. Participants An ER term for entities that participate in a relationship. Connectivity The classification of the relationship between entities. Classifications include 1:1, 1:M, and M:N. Existence-dependent A property of an entity whose existence depends on one or more other entities. Existence-independent A property of an entity that can exist apart from one or more related entities. Such a table must be created first when referencing an existence-dependent table. Strong entity An entity that is existence-independent, that is, it can exist apart from all of its related entities. Also called a regular entity. Weak (non-identifying) relationship A relationship in which the primary key of the related entity does not contain a primary key component of the parent entity. Strong (identifying) relationship A relationship that occurs when two entities are existence-dependent; from a database design perspective, this relationship exists whenever the primary key of the related entity contains the primary key of the parent entity. Weak entity An entity that displays existence dependence and inherits the primary key of its parent entity. For example, a DEPENDENT requires the existence of an EMPLOYEE. Optional participation In ER modeling, a condition in which one entity occurrence does not require a corresponding entity occurrence in a particular relationship. Mandatory participation A relationship in which one entity occurrence must have a corresponding occurrence in another entity. Relationship degree The number of entities or participants associated with a relationship. It can be unary, binary, ternary, or higher. Unary relationship An ER term used to describe an association within an entity. For example, an EMPLOYEE might manage another EMPLOYEE. Binary relationship An ER term for an association (relationship) between two entities. For example, PROFESSOR teaches CLASS. Ternary relationship An ER term used to describe an association (relationship) between three entities. For example, a DOCTOR prescribes a DRUG for a PATIENT. Recursive relationship A relationship found within a single entity type. For example, an EMPLOYEE is married to an EMPLOYEE or a PART is a component of another PART. [Show Less]
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WGU C170 - PRE-ASSESSMENT questions correctly answered 2022
A salesperson is authorized to sell many products and a product can be sold by many salespersons. Which kind of binary relationship does this scenario d... [Show More] escribe? One-to-one One-to-many Many-to-many One-to-one binary Many-to-many Which two examples are attributes? Choose 2 answers A person attending a meeting An employee number A sales meeting A meeting code An employee number A meeting code Which delete rule sets column values in a child table to a missing value when the matching data is deleted from the parent table? Restrict Cascade Matching Set-to-Null Set-to-Null Refer to the given SQL statement. CREATE TABLE member ( member_id INT UNSIGNED NOT NULL AUTO_INCREMENT, PRIMARY KEY (member_id), last_name VARCHAR(20) NOT NULL, first_name VARCHAR(20) NOT NULL, suffix VARCHAR(5) NULL, expiration DATE NULL, email VARCHAR(100) NULL, street VARCHAR(50) NULL, city VARCHAR(50) NULL, state VARCHAR(2) NULL, zip VARCHAR(10) NULL, phone VARCHAR(20) NULL, interests VARCHAR(255) NULL ); Which two columns are created as something other than variable-length strings in this statement? Choose 2 answers member_id last name suffix expiration email city member_id expiration Employee_ID Employee_Name Office_Address 12342 Jacob 54123 Main Street 12346 Michael 354 Center Avenue 12846 Ethan 54123 Main Street 12887 Joshua 54123 Main Street 12894 Daniel 354 Center Avenue 13097 Alexander 354 Center Avenue 13112 Anthony 54123 Main Street 13411 William 354 Center Avenue 13987 Christopher 354 Center Avenue 13998 Matthew 54123 Main Street This database table has ten different employee numbers in the first column. Employee_ID is the primary key. In addition, it has ten different names in the second column and two office addresses repeated five times each in the third column. Which action should be used to translate this data into third normal form? Move the data from the third column into the first column. Move the data from the third column into its own table. Move the data from the first two columns into separate tables. Move the data from the second column into the third column. Move the data from the third column into its own table. A database manager starts to convert data that has been normalized into a form that conforms to the relational model. A simple primary key has been established and all the repeating groups have been deleted. In which form is this data? First normal form Second normal form Third normal form Fourth normal form Second normal form Two attributes in two related tables have the exact same domain of values. The attribute is a primary key in one table. Which kind of key is the attribute in the other table? Foreign Primary Compound Composite Foreign Which command creates a database only if it does not already exist? IF NOT EXISTS db_name ; CREATE DATABASE IF NEW db_name ; CREATE DATABASE IF NOT EXISTS db_name ; IF NOT EXISTS CREATE DATABASE db_name ; CREATE DATABASE IF NOT EXISTS db_name ; Refer to the given SQL statement. SELECT PRODNUM, PRODNAME FROM PRODUCT Which line should be added to the end of the statement to return the product numbers and product names for products that cost 20 dollars? WHERE PRODCOST=20; AND PRODCOST=20; WHERE PRODCOST>=20; AND PRODCOST>=20; WHERE PRODCOST=20; What does WHERE identify in a basic SQL SELECT statement? The associative entity The rows to be included A table's intersection data A range of included columns The rows to be included Refer to the given SQL statement. SELECT EMPNUM FROM EMPLOYEE Which line added to the end of the statement returns employee numbers of at least 1000? WHERE EMPNUM = 1000+; WHERE EMPNUM > 1000; WHERE EMPNUM => 1000; WHERE EMPNUM >= 1000; WHERE EMPNUM >= 1000; Refer to the given SQL statement. SELECT PRODNUM, SUM(QUANTITY) FROM SALESPERSON Which line, when added to the end of the statement, returns the total number of each kind of product by product number? SUM PRODNUM; COUNT PRODNUM; ORDER BY PRODNUM; GROUP BY PRODNUM; GROUP BY PRODNUM; Which data definition language statement affects databases or objects in them? SELECT INSERT ALTER NULL ALTER What does the DELETE statement do? It removes views. It removes rows from a table. It removes columns from a table. It removes columns not named in the column list. It removes rows from a table. Which condition must be in effect to use the INSERT INTO ... VALUES syntax for an INSERT statement? The VALUES list must contain a value for each non-null valued column in the table. The VALUES list must contain a value for each row in the table. The INSERT INTO portion of the statement must generate a LOAD DATA statement. The INSERT INTO portion of the statement must refer to a sampdb database table. The VALUES list must contain a value for each non-null valued column in the table. Refer to the given SQL statement. CREATE TABLE mytbl ( f FLOAT(10,4), c CHAR(15) NOT NULL DEFAULT 'none', i TINYINT UNSIGNED NULL ); Which kind of data type is FLOAT in this statement? Decimal Integer String Data Decimal [Show Less]
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WGU C170 Data Management – Applications solved!
domain In data modeling, the construct used to organize and describe an attribute's set of possible values superkey An attribute or attributes tha... [Show More] t uniquely identify each entity in a table. Any composite key with this is also this. candidate key A minimal superkey; that is, a key that does not contain a subset of attributes that is itself a superkey entity integrity The property of a relational table that guarantees each entity has a unique value in a primary key and that the key has no null values referential integrity A condition by which a dependent table's foreign key must have either a null entry or a matching entry in the related table data dictionary A DBMS component that stores metadata. It contains the data definition & their characteristics and relationships; may also include data external to the DBMS system catalog A detailed system data dictionary that describes all objects in a database homonym The use of the same name to label different attributes, much like similar-sounding words with different meanings synonym The use of different names to identify the same object, such as an entity, an attribute, or a relationship. These should generally be avoided. not null and unique Any candidate key must have these two constraints enforced cardinality Term for how many instances of one object are related to instances of another object (maximum) modality Term for whether an instance of a specific entity is optional or mandatory in a relationship (minimum) connectivity Term for the classification of the relationship between entities. Classifications include 1:1, 1:M, and M:N CREATE SCHEMA AUTHORIZATION SQL command to create a database schema DEFAULT SQL option to define a default value for a column (when no value is given) CHECK SQL command to validate data in an attribute, used during table column creation CREATE TABLE AS SQL command to create a new table based on a query in the user's database schema HAVING SQL option that restricts a selection of grouped rows based on a condition EXISTS SQL option that checks whether a subquery returns any rows DECIMAL SQL data type like the NUMBER specification, but the storage length is a minimum specification True True or false: if an INSERT or SELECT command is embedded inside a program for later use, the attribute list should always be used, as the table may change over time inner join A join operation in which only rows that meet a given criterion are selected. The most common type of join outer join A join operation that produces a table in which all unmatched pairs are retained; unmatched values in the related table are left null cross join A join operation that returns the Cartesian product of two sets or tables natural join Join type that returns only the rows with matching values in the matching columns; the matching columns must have the same names and similar data types left, right, full Name the three types of outer joins ALL This operator can be used to compare something to every returned row of a subquery ANY This operator can be used to compare something to a list of values and return any rows that satisfy the criteria correlated subquery A subquery that executes once for each row in the outer query UNION SQL statement that combines rows from two or more queries without including duplicate rows, as long as the queries return the same # of attributes and similar data types UNION ALL SQL statement similar to UNION but retaining duplicate rows [Show Less]
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WGU Data Management - Applications - C170 OA GSA1 correctly answered 2022
Add New Row INSERT INTO table_name (column1, column2, ...) VALUES (value1, value2, value3, ...); Update Row UPDATE table_name SET column1 = valu... [Show More] e1, column2 = value2, ... WHERE condition; Delete Row DELETE FROM table_name WHERE condition; Inner Join SELECT column_name(s) FROM table1 INNER JOIN table2 ON table1.column_name = table2.column_name; CREATE VIEW CREATE VIEW viewname AS SELECT Col1, Col2 FROM table WHERE condition; Concatenate CONCAT(Col1, Col2) AS NewColumnName; Create Index CREATE INDEX index_name ON table_name (column1, column2, ...); Create Database CREATE DATABASE databasename; Drop Database DROP DATABASE databasename; Create Table CREATE TABLE table_name ( column1 datatype, column2 datatype, column3 datatype, .... ); Set Primary Key CREATE TABLE Persons ( ID int NOT NULL, LastName varchar(255) NOT NULL, FirstName varchar(255), Age int, PRIMARY KEY (ID) ); Set Foreign Key CREATE TABLE Orders ( [Show Less]
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WGU Course C170 - Data Management (Applications) questions correctly answered 2022
A salesperson is authorized to sell many products and a product can be sold by many salespersons. Which kind of binary relationship does this scenario d... [Show More] escribe? A One-to-one B One-to-many C One-to-one binary D Many-to-many D Which kind of relationship is displayed in this entity-relationship diagram? A Many-to-many unary B Many-to-many binary C One-to-one unary D One-to-one binary A 01:08 01:41 Which kind of relationship is displayed in this entity-relationship diagram? A Binary many-to-many B Unary one-to-one C Ternary many-to-many D Ternary one-to-one D Unary many-to-many E Binary one-to-one B How is this portion of the entity-relationship diagram read, from left to right? A At least one book was written by an author. B Only one book was written by one author. C No books are written by an author. D One book was written by more than one author. A Which two examples are attributes? Choose 2 answers 1 A meeting code 2 A person attending a meeting 3 An employee number 4 A sales meeting A 1,3 B 2,4 A Which delete rule sets column values in a child table to a missing value when the matching data is deleted from the parent table? A Restrict B Cascade C Matching D Set-to-Null D In this entity-relationship diagram, Salesperson 361 is related to two customers. The table follows the restrict delete rule. What happens if someone tries to delete Salesperson 361 from the customer records? A The delete occurs immediately. B The lack of a salesperson is flagged for later. C A new salesperson is assigned instead. D The delete is prohibited. D Refer to the given SQL statement. CREATE TABLE member(member_idINT UNSIGNED NOT NULL AUTO_INCREMENT,PRIMARY KEY (member_id),last_nameVARCHAR(20) NOT NULL,first_nameVARCHAR(20) NOT NULL,suffixVARCHAR(5) NULL,expirationDATE NULL,emailVARCHAR(100) NULL,streetVARCHAR(50) NULL,cityVARCHAR(50) NULL,stateVARCHAR(2) NULL,zipVARCHAR(10) NULL,phoneVARCHAR(20) NULL,interestsVARCHAR(255) NULL); Which two columns are created as something other than variable-length strings in this statement? Choose 2 answers 1 member_id 2 expiration 3 suffix 4 email 5 last name 6 city A 1,2 B 3,4 A This database table has ten different employee numbers in the first column. Employee_ID is the primary key. In addition, it has ten different names in the second column and two office addresses repeated five times each in the third column. Which action should be used to translate this data into third normal form? A Move the data from the third column into the first column. B Move the data from the third column into its own table. C Move the data from the first two columns into separate tables. D Move the data from the second column into the third column. B A database manager starts to convert data that has been normalized into a form that conforms to the relational model. A simple primary key has been established and all the repeating groups have been deleted. In which form is this data? A First normal form B Second normal form C Third normal form D Fourth normal form B Two attributes in two related tables have the exact same domain of values. The attribute is a primary key in one table. Which kind of key is the attribute in the other table? A Compound B Composite C Primary D Foreign D In this entity-relationship diagram, many salespersons are shown as working in at least one office. How is the relationship between salespersons and offices represented in the diagram? A It is linked through the salesperson ID. B It is indicated by the tables' adjacency. C It is undefined. D It is linked through the office ID. D? 00:02 01:41 Which command creates a database only if it does not already exist? A IF NOT EXISTS CREATE DATABASE db_name ; B CREATE DATABASE IF NEW db_name ; C IF NOT EXISTS db_name ; D CREATE DATABASE IF NOT EXISTS db_name ; A Refer to the given SQL statement. SELECT PRODNUM, PRODNAME FROM PRODUCT Which line should be added to the end of the statement to return the product numbers and product names for products that cost 20 dollars? A WHERE PRODCOST>=20; B WHERE PRODCOST=20; C AND PRODCOST=20; D AND PRODCOST>=20; B What does WHERE identify in a basic SQL SELECT statement? A A table's intersection data B The associative entity C A range of included columns D The rows to be included D Refer to the given SQL statement. SELECT EMPNUM FROM EMPLOYEE Which line added to the end of the statement returns employee numbers of at least 1000? A WHERE EMPNUM > 1000; B WHERE EMPNUM >= 1000; C WHERE EMPNUM => 1000; D WHERE EMPNUM = 1000+; B Refer to the given SQL statement. SELECT PRODNUM, SUM(QUANTITY) FROM SALESPERSON Which line, when added to the end of the statement, returns the total number of each kind of product by product number? A ORDER BY PRODNUM; B GROUP BY PRODNUM; C COUNT PRODNUM; D SUM PRODNUM; B Which data definition language statement affects databases or objects in them? A INSERT B NULL C ALTER D SELECT C What does the DELETE statement do? A It removes rows from a table. B It removes views. C It removes columns not named in the column list. D It removes columns from a table. A Which condition must be in effect to use the INSERT INTO ... VALUES syntax for an INSERT statement? A The VALUES list must contain a value for each non-null valued column in the table. B The INSERT INTO portion of the statement must refer to a sampdb database table. C The INSERT INTO portion of the statement must generate a LOAD DATA statement. D The VALUES list must contain a value for each row in the table. A Refer to the given SQL statement. CREATE TABLE mytbl ( f FLOAT(10,4), c CHAR(15) NOT NULL DEFAULT 'none', i TINYINT UNSIGNED NULL ); Which kind of data type is FLOAT in this statement? A Decimal B Data C String D Integer A Which two SQL data types can represent images or sounds? Choose 2 answers 1 FLOAT 2 TERNARY 3 SOUNDBLOB 4 TINYBLOB 5 BINARY 6 INT A 4,5 B 1,2 A Refer to the given SQL statement. CREATE TABLE CUSTOMER (CustomerIDINT NOT NULL AUTO_INCREMENT, LastName VARCHAR(100) NOT NULL, FirstName VARCHAR(100) NOT NULL, PRIMARY KEY( CustomerID )); Which component of the command indicates the table's name? A TABLE CUSTOMER B CustomerID C CUSTOMER D INT C Which method creates an empty copy of a table and then populates it from the original table? A CREATE TABLE ... INTO followed by INSERT INTO: B INSERT TABLE ... LIKE followed by SELECT: C INSERT TABLE ... SELECT followed by INSERT INTO ... LIKE: D CREATE TABLE ... LIKE followed by INSERT INTO ... SELECT : D [Show Less]
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