WGU C170 Data Management - Applications

domain In data modeling, the construct used to organize and describe an attribute's set of possible values superkey An attribute or attributes that 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