The SELECT operator yields a vertical subset of a table. The DIFFERENCE operator subtracts one table from the other.
In a natural join, the column on which the join was made occurs twice in the newtable. The DIVIDE operation uses one single column table (e.g., column "a") as the divisor and one two column table (e.g., columns "a" and "b") as the dividend. To be considered minimally relational, the DBMS must support the key relational operators _____, PROJECT, and JOIN.SELECT_____, also known as RESTRICT, yields values for all rows found in a table that satisfy a given condition.SELECT_____ returns only the attributes requested, in the order in which they are requested. When two or more tables share the same number of columns, and when their corresponding columns share the same or compatible domains, they are said to be _____ . _____ are especially useful when you are trying to determine what values in related tables cause referential integrity problems. A(n) _____ only returns matched records from the tables that are being joined. The relational operators have the property of _____; that is, the use of relational algebra operators on existing relations (tables) produces new relations. PRODUCT yields all possible pairs of rows from two tables, also known as the _____ product. _____ is the real power behind the relational database, allowing the use of independent tables linked by common attributes. A(n) _____ links tables on the basis of an equality condition that compares specified columns of each table. A data dictionary is sometimes described as "the database designer's database" because it records the design decisions about tables and their structures. A _____ contains at least all of the attribute names and characteristics for each table in the system. In a database context, the word _____ indicates the use of the same attribute name to label different attributes.
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- Relational Database, Relational model, primary key