Oracle PL/SQL – Cursors

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Cursors
A Cursor in PL/SQL is used to return rows of data from an SQL query (a ResultSet). You can iterate over a Cursor in a PL/SQL using a LOOP or return a Cursor to a calling entity such as a Java application. There are two types of Cursors in PL/SQL. Implicit and Explicit, the differences are as follows:

Implicit Cursors
Implicit Cursors are indirectly created by Oracle when an INSERT, UPDATE, DELETE, or SELECT statement is executed. However, in the case of a SELECT statement implicit Cursors are only created when one row is returned, if more than one row is returned we must Explicitly declare a Cursor.


Explicit Cursors
Explicit Cursors are explicitly declared in PL/SQL code and they return multiple rows from a SELECT statement. Once these rows are returned, the can be itereated over one at time using a LOOP construct inside of a Stored Procedure, Package, Function, etc. Or they can be returned to a calling application or procedure.

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