WGU C170, Exam Review Questions and answers. VERIFIED. Latest updates.

WGU C170, Exam Review Questions and answers. VERIFIED. Latest updates. 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 application's query will access the database at run time. Alias - -An alternative name for a column or table in a SQL statement. ALTER TABLE - -The SQL command used to make changes to table structure. When the command is followed by a keyword (ADD or MODIFY), it adds a column or changes column characteristics. AREA - -In DB2, a named section of permanent storage space that is reserved to store the database. Atomic attribute - -An attribute that cannot be further subdivided to produce meaningful components. For example, a person's last name attribute cannot be meaningfully subdivided. Atomicity - -The transaction property that requires all parts of a transaction to be treated as a single, indivisible, logical unit of work. All parts of a transaction must be completed or the entire transaction is aborted. 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. Base tables - -Tables on which the view is based batch update routine - -A routine that pools transactions into a single batch to update a master table in a single operation. BETWEEN - -In SQL, a special comparison operator used to check whether a value is within a range of specified values. binary relationship - -An ER term for an association (relationship) between two entities. For example, PROFESSOR teaches CLASS. Bitmap index - -An index that uses a bit array (0s and 1s) to represent the existence of a value or condition. Boolean Algebra - -A branch of mathematics that uses the logical operators OR, AND, and NOT. Boyce-Codd Normal Form (BCNF) - -A special type of third normal form (3NF) in which every determinant is a candidate key. A table in BCNF must be in 3NF. See also determinant. Candidate Key - -A minimal superkey; that is, a key that does not contain a subset of attributes that is itself a superkey. Cardinality - -A property that assigns a specific value to connectivity and expresses the range of allowed entity occurrences associated with a single occurrence of the related entity. Cascading order sequence - -A nested ordering sequence for a set of rows, such as a list in which all last names are alphabetically ordered and, within the last names, all first names are ordered. Closure - -A property of relational operators that permits the use of relational algebra operators on existing tables (relations) to produce new relations. Composite Attribute - -An attribute that can be further subdivided to yield additional attributes. For example, a phone number such as may be divided into an area code (615), an exchange number (898), and a four-digit code (2368). Compare to simple attribute. 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. See also linking table. Composite Identifier - -In ER modeling, a key composed of more than one attribute. Composite Key - -A multiple-attribute key. Correlated Subquery - -A subquery that executes once for each row in the outer query.