WGU c170 Bundled Docs With Complete Solution

WGU c170 Bundled Docs with complete solution Area - CORRECT ANSWERS named section of permanent storage space that is reserved to store the database Associative Entity - CORRECT ANSWERS Also known as composite entity Bridge Entity - CORRECT ANSWERS Another name for a composite entity candidate key - CORRECT ANSWERS A minimal superkey; that is, a key that does not contain a subset of attributes that is itself a superkey. closure - CORRECT ANSWERS A property of relational operators that permits the use of relational algebra operators on existing tables (relations) to produce new relations. composite entity - CORRECT ANSWERS 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 key - CORRECT ANSWERS A multiple attribute key dependent - CORRECT ANSWERS An attribute whose value is determined by another attribute. determination - CORRECT ANSWERS 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 - CORRECT ANSWERS In relational algebra, an operator used to yield all rows from one table that are not found in another union-compatible table. DIVIDE - CORRECT ANSWERS 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 - CORRECT ANSWERS In data modeling, the construct used to organize and describe an attributes set of possible values. entity integrity - CORRECT ANSWERS 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 - CORRECT ANSWERS A join operator that links tables based on an equality condition that compares specified columns of the tables. flags - CORRECT ANSWERS 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) - CORRECT ANSWERS An attribute or attributes in one table whose values must match the primary key in another table or whose values must be null. full functional dependence - CORRECT ANSWERS A condition in which an attribute is functionally dependent on a composite key but not on any subset of the key. functional dependence - CORRECT ANSWERS Within a relation R, an attribute B is functionally dependent on an attribute A if and only if a given value of the attribute A determines exactly one value of the attribute B. The relationship "B is dependent on A" is equivalent to "A determines B" and is written as A B. homonyms - CORRECT ANSWERS The use of the same name to label different attributes. Homonyms should be avoided in databases index - CORRECT ANSWERS 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 - CORRECT ANSWERS Also called an index. inner join - CORRECT ANSWERS 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 - CORRECT ANSWERS In relational algebra, an operator used to yield only the rows that are common to two union-compatible tables. JOIN - CORRECT ANSWERS 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 column(s) - CORRECT ANSWERS Columns that join two tables. The join columns generally share similar values. key - CORRECT ANSWERS one or more attributes that determine other attributes key attribute - CORRECT ANSWERS The attributes that form a primary key left outer join - CORRECT ANSWERS A join that includes all of the rows from the first table in the query and only those records from the second table that match the join field in the first table. linking table - CORRECT ANSWERS In the relational model, a table that implements an M:M relationship. natural join - CORRECT ANSWERS A relational operation that yields a new table composed of only the rows with common values in their common attribute(s). null - CORRECT ANSWERS The absence of an attribute value. Note that a null is not a blank. outer join - CORRECT ANSWERS Returns a set of records that include what an inner join would return but also includes other rows for which no corresponding match is found in the other table. predicate logic - CORRECT ANSWERS Used extensively in mathematics to provide a framework in which an assertion (statement of fact) can be verified as either true or false.