|SAS/ACCESS Interface to CA-DATACOM/DB: Reference
Deleting and inserting data records in a CA-DATACOM/DB table
is a straightforward process for the SAS System as well as for CA-DATACOM/DB.
However, several considerations are worth noting.
- When inserting a new row in the SAS System, you normally visualize
the new data being appended at the end of the SAS data file. However, CA-DATACOM/DB conventions
affect the appearance of a procedure such as FSEDIT.
When you include a WHERE clause or criteria that require a Select file,
the customary SAS behavior applies. Otherwise, newly added data records appear
in order by the Native Key, not at the end. The new records are always inserted
in the table in the proper place, in order by the Native Key. Including or
not including a WHERE clause simply determines how the table looks to the
Note: If you are going to use a view descriptor to insert
new data records, you must select at least one key (or the fields that make
up the key) for that view descriptor. Select the Master Key if the Master
Key values must be unique. If you request repositioning (that is, the DDBLOAD=
option is set to zero or allowed to default to zero), either the default key
must be selected or all of the fields that it comprises must be selected.
An ADD cannot be processed if DDBLOAD equals 0 and the Default Key field
is set to blanks.
- If INCLUDE-NIL-KEY equals YES, null values are indexed. However,
if DUPE-MASTER-KEY equals NO, duplicate values cannot be indexed. That is,
if you insert two records with missing values for the Master Key, the second
insert fails. Native Key values must be unique, another reason that the second
insert of a missing value fails.
- In order for you to even see newly added records while in an interactive
procedure, the interface view engine does some fairly complex processing that
is referred to as repositioning. Repositioning means retrieving a record
immediately after it has been inserted, so that it is visible to you. This
is important in an interactive procedure, but not as important in a procedure
such as PROC APPEND. Therefore, to save processing time, a DDBLOAD= data
set option is available that allows you to turn repositioning on and off.
Setting the DDBLOAD= data set option causes the APPEND procedure, for example,
to process faster and more efficiently. For more information on the DDBLOAD=
data set option, see Data Set Options.
- Deleting a data record removes the record from the
The deleted data record is no longer available for access even though it
may have satisfied the WHERE clause selection criteria before it was removed.
Copyright 1999 by SAS Institute Inc., Cary, NC, USA. All rights reserved.