Chapter 3 DBMS Reference Guide

DropColnChck

Statement for dropping a column check in an alter table statement. This statement is used in the database modification script when the check parameters have been removed on a column.

If DropColnChck is empty, the Modify database process does the following:

• Drops the foreign key constraints
• Creates a temporary table with the same structure and columns as the table before the check parameter deletion
• Inserts the rows from the old table to the new temporary table
• Drops the actual table
• Creates a new table without any check parameters on the modified column
• Inserts the rows from the temporary table to the new table
• Creates the indexes and the constraints on the new table

Example

In Sybase Adaptive Server Anywhere 6:

DropColnChck = alter table [%QUALIFIER%]%TABLE%
modify %COLUMN% check null

The %COLUMN% variable is the name of the column defined in the column list window of a table.

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