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CHAPTER 13 PL/SQL Programming Language > PL/SQL Variables: Types, Assignments, ...

PL/SQL Variables:
Types, Assignments, and Operators

PL/SQL supports many more data types than Oracle's SQL dialect does. These variables can be classified into two main groups: scalar and composite.

A scalar variable contains one and only one thing. In Java, primitives are scalar variables. Characters, integers, and various number data types are scalar variables in most programming languages. Strings are also scalar variables in the context of relational databases.

A composite variable contains more than one scalar or other composite variable in some type of data structure. Structures can be arrays, reference cursors, and user-defined types such as arrays, records, or objects.

Some data types are unconstrained, but others are constrained. Constrained data types derive specialized behavior from their generalized or unconstrained data type. For example, a user-defined data type of positive integers is a specialization of an integer data type. An unconstrained data type doesn't place artificial limits on the range of a data type.


  

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