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Empty Table Key

The primary table key of a standard table can be empty. An empty table key does not contain any key fields.

Note

Sorted keys and hash keys are never empty, regardless of whether they are primary or secondary.

Declaration

An empty primary table key can be created as follows:

Notes on Use

Uncritical use

An empty primary table key can be used to handle a table like an array. This means that filling the table and other access do not rely on an order determined by key values. In this case, an empty internal table key can be used in all statements that determine (implicitly or explicitly) the order in which the internal table is accessed.

Notes

Example

A particularly prominent example is the statement LOOP AT itab, which when used implicitly or explicitly (using USING primary_key) defines the processing order with respect to the primary table index, but otherwise has no effect.

Critical use

In the following statements, which work with the primary table key without specifying the key fields explicitly, specifying an empty primary table key is critical and generally produces unexpected behavior. An empty table key that can be identified statically produces a syntax check warning.

Note

The statements described above can be particularly unpredictable when using the standard key (which itself can be declared implicitly) to declare an empty internal table key.