2575930 - Message no. DT245 DB length of the key of table & is too large

When you activated a customizing table, you encountered error message like this:

DB length of the key of table & too large (>900)

Message No. DT245
Diagnosis
The sum of the DB field lengths of all key fields of the table is too large.
The special features of the different database systems are used in the calculation.
Procedure
You must either remove fields from the key or shorten the field lengths of the key fields.

ABAP system

DT245,DB length of the key of table & too large,ddlength_to_dblength_more_info,DD_TBFD_CHK_KEY , KBA , BC-DWB-DIC-AC , ABAP Dictionary Activation and Conversion , Problem