Modifying Tables with DDL

You can modify a table definition by altering, adding, or dropping columns and constraints. Constraints allow you to enforce integrity by creating rules for a table. The procedures in the following sections illustrate how to use Jet 4.0 SQL DDL statements to:

■ Add new columns to a table

■ Change the column's data type

■ Change the size of a text column

■ Delete a field from a table

■ Add a primary key to an existing table

■ Add a unique, multiple-field index to an existing table

■ Delete an indexed column

■ Set a default value for a column in a table

Change the seed and increment value of AutoNumber columns

0 0

Post a comment