Oracle / PLSQL: ORA-01404 Error Message

Learn the cause and how to resolve the ORA-01404 error message in Oracle.

Description

When you encounter an ORA-01404 error, the following error message will appear:

• ORA-01404: ALTER COLUMN will make a concatenated index too large

Cause

You tried to increase the length of a column that is used in an index. This made the concatenated index larger than its maximum allowed size of 255.

The size of the index is calculated as follows:

• Date fields are a length of 7.
• Character fields are their defined length.
• Numeric fields are a length of 22.

The total index length is calculated as the sum of the individual fields as defined above + the number of columns in the index.

Resolution

The option(s) to resolve this Oracle error are:

Option #1

You can drop the index and then increase the length of the column. The only problem with this method is that you will no longer be able to re-create your index.