The @COMPARE command performs the logical processing on two ISN lists that have been previously created with the @FIND or @COMPARE commands with the SAVE option.

The ISN lists to be processed may not be created with the SORTED option of the @FIND command, because they must be in ascending ISN sequence. The two ISN lists must contain ISNs from the same file.

The syntax of the command is as follows:

The result of the @COMPARE command is a new ISN list, stored in the ISN buffer and the WORK data set. The record buffer will automatically be presented with the first record. To access subsequent records, use the @READNEXT command with the same nnnn. The EOFnnnn indication is turned on when all the records are read or no ISNs result from a logical operation.

COMMAND-IDxxxx and COMMAND-IDyyyy are necessary keywords, where xxxx and yyyy are identify the @FIND commands that created the ISN lists.

The logical operations are AND, OR, and NOT.

If the file is protected , the use the PASSWORD parameter.

If the file is ciphered, use the CIPHER parameter, providing a valid cipher code.

The command automatically reads the first record. To hold the record, use the NOREAD option followed by a @READNEXT HOLD command.

The NOREAD option causes the command to be executed without reading the first record. This record is read during the execution of the first @READNEXT command.

The GETNEXT option causes Adabas Pre-Compiler to generate code to work with the Adabas GETNEXT option. In this case, the ISN buffer is not used. You may use PREFETCH and SECURITY BY VALUE.

For example:

In this example, the AND operator applies to the result of the two @FIND commands. The records are then read. @ADADCL5 and @ADADCL8 do not contain any field expressions. In @ADADCL9, the field expression defines the logical record to be read and the search criteria is not relevant.