Extract a MARC record identified by BIB_ID, MFHD_ID or AUTH_ID

• GetBibBLOB(BIB_ID)
• GetMFHDBLOB(MFHD_ID)
• GetAuthBLOB(AUTH_ID)

These three functions aren't useful on their own.  They ask Voyager for a MARC record.  You use one of these three as a building block for the four other functions that follow.  Your query will also include at least one table in which the ID field is unique.  For example:

You'll wrap one of the following four GetField* functions around one of the above.

Extract one or more fields from that MARC record

• GetField(*MARC Record*, “300”, 1)
• GetFieldRaw(*MARC Record*, “300”, 1)
• GetFieldAll(*MARC Record*, “300”)

Extract a subfield from that field

• GetSubField(*MARC Field*, “c”, 1)

GetField* functions synopsis:

GetField

• Gives you a single occurrence of a MARC field
• Same as GetFieldAll but get only one field
• Get entire first occurrence of 938 tag: GetField(GetBIBBLOB ([BIB_TEXT].[ BIB_ID]),”938”,1)
• Get first 650 field, subfields a and x: GetField(GetBibBlob([BIB_TEXT].[BIB_ID],"650",1,"ax")

GetFieldAll 

• Gives you all occurrences of a MARC field
• Gives you all subfields (separated by spaces)
• Get entire 938 tag: (GetFieldAll(GetBIBBLOB([BIB_TEXT].[BIB_ID]),”938”)
• Get all of the 866s in a MFHD: GetFieldAll(GetMFHDBlob([MFHD_MASTER].[MFHD_ID]),'866')

GetFieldRaw

• Gives you one occurrence of a MARC field, including the tag, indicators and subfield coding
• It is the only way to get the indicators
• It is the only function that works with GetSubField
• Get the third 650 field in a bib record: GetFieldRaw(GetBibBlob([BIB_TEXT].[BIB_ID]),'650',3)

GetSubField 

• Gives you one occurrence of a MARC subfield
• Get specified subfield "a" of 938 tag occurrence: GetSubField(GetFieldRaw(GetBIBBLOB ([BIB_TEXT].[ BIB_ID]),”938”,1),”a”,1)

Example of a BLOB query using the GETFIELD function

This query extracts the 300 field:

Example of Using GETFIELDALL function in a query

This query gets the title, call number of all 5xx (note) fields from BIB records:

Notice that second parameters can be truncated to do generic matching.  In this example to get any 5xx field, you can use "5". Use an empty string ("") to match any subfield.

Note also that multiple fields are put on multiple rows and may be "hidden" until the row is made taller:

Example of Using the GETSUBFIELD function

GetSubfield must be used in combination with GetFieldRaw; both of these functions require you to specify "Which" matching field/subfield you want:

Notice in the above we imbed the call to "larger" functions into the "smaller" function. For example: GetSubField(GetFieldRaw(GetBibBLOB(BIB_ID),“300”,1),“c”,1):

Example of Checking for field presence

This query looks for MFHDs with multiple (more than one) 866 fields; we don't care what is in the the second field, just that it is there:

Example of Using a Criteria to screen for field content

This query looks for books under 21 centimeters:

Note that adding a criterion to a BLOB query makes it run even slower.  That's why it is recommended that you run BLOB queries on a subset of your data by using a Make Table query and running your BLOB query against that table.

Reading a BLOB query

Example: The second $x from the first 650 in a BIB record.

GetSubField(GetFieldRaw(GetBibBlob([BIB_TEXT].[BIB_ID]),'650',1),'x',2)

Work from the inside outward:

Are we blobbing a bib, MFHD, or authority? A bib.
GetBibBlob: Which one? The one with this bib_id.

Working outward:
GetFieldRaw: Which field? 650. Which occurrence? The first.

Working outward:
GetSubField: Which one? Subfield x. Which occurrence of subfield x in this field? The second.