Using the 'Data' rule in MARC Global and MARC Review patterns

In version 234, a new matching rule was added to the pattern match forms in MARC Global and MARC Review.

The purpose of this rule is to make it possible to pattern match two fields without knowing what data is contained in those fields.

For example, lets say you want to identify all the records where the content of the 090 field is the same as the content of the 050 field.
Start MARC Review/MARC Global, and fill out the first pattern as follows:

Note the 'Data' item in the Rule listbox. Now click 'Next pattern' and set up the 090 as follows:

Note the two new rules in the Rule listbox: 'And/Data' and 'Not/Data'. The first rule finds fields where the data is the same, and the second rule finds fields where the data is not the same (So, in our example, to find 090s that differed from the 050s, we would use the 'Not/Data' rule instead)).

The Data rule is context-sensitive. On the first pattern, this rule will always be 'Data'. On the second pattern, this rule will be either 'And/Data' or 'Not/Data'.

If we go ahead and run these patterns against a file, the output would look something like this:

MARC Source filename: D:\Marc\LD\hybrids-5716_All.mrc
Review Description: AND 050, MATCHES 090, Display: 050, 090

[Record Number 1442]
050  4$aDK510.34$b.K3 2006
090   $aDK510.34$b.K3 2006

[Record Number 3485]
050 14$aPJ5054.S384$bR6617 2006
090   $aPJ5054.S384$bR6617 2006
...

Note that the pattern that we setup ignores indicators. If you want to match indicators also, you will need to enter them specifically on the pattern forms.

What makes this rule more useful, however, is that it can also be used as the basis for a MARC Global action. For example, given the pattern above, we could then use MARC Global to delete either tag, or perform any other MG action.

Note that the 'Data' rule is only applicable when there are at least two patterns. If 'Data' is used as a rule in a review that contains only one pattern, or where the second pattern does not use one of the 'Data' rules, an error message will pop-up.