Advanced Topics › Enhanced Data Set Integrity Facility › How You Apply EDIF Processing to Data Sets › How EDIF Merges and Overrides Statements

How EDIF Merges and Overrides Statements

If several statements affect a data set, EDIF merges these statements to determine which processing options to use. This allows you to accomplish the following tasks:

• Perform additional processing for selected data sets. For example, you can specify one statement that applies to all data sets and then another that performs special additional processing for the SYS1.LINKLIB data set.
• Override processing that is in effect for a data set. For example, you can prevent unauthorized updates for all data sets and then override this processing for data sets that start with the prefix SYS1.

When overriding processing options for a data set, the order in which EDIF merges its processing statements is important. EDIF builds a list of applicable options for a data set by prioritizing processing statements as follows:

1. DEFAULT
2. DSORG
3. PREFIX
4. SUFFIX
5. PATTERN
6. DATASET

You can use statements at the end of this list to override processing from a previous statement. For example, you can set options for all data sets on a DEFAULT statement and override that processing for certain data sets through PATTERN and DATASET statements.

EDIF uses, at the most, one of each type of statement when it processes a data set. For example, if the data set name on three PREFIX statements matches, then EDIF uses only one of these PREFIX statements for that data set. If you specify more than one of the same type of statement, keep the following guidelines in mind to ensure that EDIF uses the correct statement:

• For PREFIX and SUFFIX statements, EDIF uses the statement that has the longest matching data set name. Therefore, make sure that the data set name or partial data set name you specify is as exact as possible.
• For PATTERN statements, EDIF uses the first statement that matches the name of the data set. Therefore, place the most specific PATTERN statements first and the least specific last.