| SAS/ACCESS Interface to CA-DATACOM/DB: Reference |
A User Requirements Table
(URT) is a load module that is required by CA-DATACOM/DB.
The URT is loaded by the interface view engine and passed to CA-DATACOM/DB when
a table is opened. It contains information about how the table is to be accessed.
Various values in the URT, such as number and size of buffers, can affect
performance.
You can specify a URT in various ways; these are given below. The interface
view engine looks for a URT in the order of the situations described. Note
that a specific URT always overrides a generic or a default URT.
- You can designate a specific URT with a data set option when you
run a SAS program. For details, see the DDBURT= data set option in Data Set Options.
- You can designate a
specific URT by saving its name in the view
descriptor.
- You can create special URTs named UStttnnn or UWtttnnn and the interface view engine will look for them in the load
library. US means sequential processing, and UW means WHERE clause processing. ttt is the CA-DATACOM/DB name
for the table, and nnn is the database ID. If the interface
view engine cannot find such a URT and you have not specified a particular
URT, it generates one, as discussed below.
- You can let the interface view engine create its own URT. It
uses two default load modules (named USDDBEXT and UWDDBEXT) that are delivered
with the product.
Note: ACCESS=SEQ is not allowed. Use ACCESS=RANSEQ.
The engine never alters the type of ACCESS that you specify in a URT. Also,
AUTODXC=NO is not allowed in a URT. ![[cautionend]](../common/images/cautend.gif)
For more information on URTs, see the appropriate CA-DATACOM/DB
documentation.
Version 5 URTs work with the Version 8 interface with the following
exceptions:
- Version 5 URTs probably have the UPDATE= parameter set to NO.
This will fail if you open a view descriptor for update in Version 8. For
security reasons, the interface view engine does not upgrade UPDATE=NO to
UPDATE=YES. However, the interface view engine does downgrade UPDATE=YES
to UPDATE=NO if appropriate in order to prevent possible problems.
- The ACCESS=SEQ parameter in a URT is not supported in Version
8, because additional commands are required to support the engine specifications.
Change any existing URTs to ACCESS=RANSEQ.
- The AUTODXC=NO parameter will fail with Version 8. With the SAS
locking requests, it tends to exceed CA-DATACOM/DB limits on the number of
records locked.
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
