Types of Variables in PL/SQL.

Types of Variables in PL/SQL:
1) Scalar.
2) Composite.
3) Reference.
4) LOB (large objects).

1) Scalar Data Types:

• They holds a single value.
• Main data types are those that correspond to column types in oracle server tables.
• Supports Boolean variables.

2) Composite data types:

• A variable of a composite type contains one or more scalar variables.
• Composite data types are similar to structures in ‘C’ language.
• They help in keeping all the related data items together as one collection.

3) Reference Data types:

• They hold values, acting as pointers, which designate other program items.
• They are very essential when manipulating collection of data items in sub programs.

4) LOB data types:

• They holds values called locations, specifying the location of large objects that are stored  out of line in the PL/SQL program.