Using &NDB Verbs › Change NDB NCL Processing Options

Change NDB NCL Processing Options

The &NDBCTL verb is used to alter processing options associated with the executing NCL process. Options that can be changed are:

• Issuing messages on error conditions. By default (MSG=YES), a message is sent to the environment the NCL procedure is running under. For a normal NCL procedure, this is the OCS window. The messages are also logged. By specifying MSG=LOG, error messages are only sent to the activity log.

  By specifying MSG=NO, no error messages are issued. Only database integrity messages that are sent to monitor receivers are issued.

  Handling database error conditions. By default (ERROR=ABORT), a response code greater than 29 (in &NDBRC) causes the process to be terminated with an error message.

  By specifying ERROR=CONTINUE the process retains control, but must check &NDBRC for error responses.

  &NDBOPEN is always processed as if &NDBCTL ERROR=CONTINUE is in effect, except for response 34 (already open). The same applies to &NDBCLOSE, except for response 35 (not open).

• The format that dates can be entered (by &NDBADD/&NDBUPD, and &NDBSCAN), and returned (by &NDBGET). By default (DATEFMT=*), the user's UAMS language code, or, if no specific language code is in the user definition, the system language code, determines whether dates can be entered in DD/MM/YY (UK or DATE4), or MM/DD/YY (US or DATE5) format.

  You can specify DATEFMT values of DATE1 to DATE10, UK (=DATE4), or US (=DATE5), or * (meaning as described previously).

• The need to quote values for characters, hexadecimal (FMT=HEX), hexadecimal numbers (FMT=NUM BASE=HEX) and date format data using the QUOTE operand. By specifying QUOTE=NO (the default) these data types need not be quoted and embedded blanks in NCL variables in free-form text are ignored.

  By specifying QUOTE=YES all of the previously listed data types must be quoted and embedded blanks are treated as real blanks, causing &NDBQUOTE to force-quote all non-null data.

• Tracing of the parsing of free-format text. By default (TRACE=NO), no trace messages are produced.

  By specifying TRACE=YES, a message is produced for each token in the free-form text. This message is subject to the &NDBCTL MSG= setting. The first 20 characters of each token are traced.

• Dumping a scan action table. By default (SCANDEBUG=NO), no dump is produced. By specifying SCANDEBUG=YES, a dump of the generated scan action table is produced. At completion of the scan, a second dump shows record counts.

These options allow you to easily develop applications using NDBs, and to make the procedures robust.

For example, while developing code, use MSG=YES and ERROR=ABORT. This will give useful messages and stop a procedure at the error point. From time to time, TRACE=YES can be used to track obscure syntax errors in free-form text (particularly scan expressions, and problems caused by failing to quote data containing delimiter characters).

When the code is finished, specifying MSG=NO (or MSG=LOG), and ERROR=CONTINUE allows the procedures to handle unexpected errors gracefully.

The DATEFMT= option lets you control the input and formatting of dates. The default behavior (honoring the user or system date format) is normally the best setting. However, when unloading or reloading data, &NDBCTL DATEFMT=NO lets you be independent of the current language settings.