Deletes the named constraints.

1  –  Environment

    You can use the DROP CONSTRAINT statement:

    o  In interactive SQL

    o  Embedded in host language programs to be precompiled

    o  As part of a procedure in an SQL module

    o  In dynamic SQL as a statement to be dynamically executed

2  –  Format

  DROP CONSTRAINT --> <constraint-name> -+---------------+->
                                         +-> IF EXISTS --+

3  –  Arguments

3.1  –  constraint-name

    Specifies the name of the constraint that you want to delete.

3.2  –  IF_EXISTS

    Prevents SQL command language from displaying error messages if
    the referenced object does not exist in the database.

4  –  Example

    Example 1: Deleting a constraint

    The following statement deletes the SEX_NOT_NULL constraint.

    SQL> DROP CONSTRAINT SEX_NOT_NULL;