Key Category

You use the key category to define whether the internal table defined by the table type can contain only records with a unique key, or whether the key can have duplicates.

You can define the following key categories:

• Unique:

  This table type can contain only records with a unique key.

• Non-Unique:

  A table with this table type can also contain records that do not have different keys for the table type.

• Not specified:

  The key category is unique or non-unique. This defines a generic table type .

  Caution

  Only certain combinations of access mode and key category are allowed. These are listed in the following table.

If the primary key of a standard table or hash table is not specified, you have to select key category Not specified.