ROWID columns
Informix®
When creating a table, Informix automatically adds a
ROWID integer column (applies to non-fragmented tables only).
The ROWID column is auto-filled with a unique number and can be used like a
primary key to access a given row.
ROWID usage was a
common practice in the early days of Informix
4GL programming. Today it is recommended to define all your database tables with a
PRIMARY KEY to uniquely identify rows.With Informix, the SQLCA.SQLERRD[6]
register contains the ROWID of the last row affected by an INSERT,
UPDATE or DELETE statement.
PostgreSQL
With PostgreSQL versions prior to version 12, tables can be created with an OID
(Object Identifier) column, that is similar to Informix
ROWID columns.
OID columns are no
longer supported, and the ROWID emulation is no longer possible with the PostgreSQL ODI
driver.The type of PostgreSQL OID columns is INTEGER.
OID columns are no longer
enabled by default. To have OID columns created for tables, you need to set the
default_with_oid parameter to "on" in the
postgresql.conf file.The PostgreSQL C API provides the PQoidValue() function, to get the
OID of the last inserted row. Unlike Informix SQLCA.SQLERRD[6], PostgreSQL does not return the
OID of the last row modified by an UPDATE, or removed by a
DELETE.
Solution
For PostgreSQL versions prior to version 12, the database can automatically convert
ROWID keywords to OID.
If PostgreSQL OID columns are available and enabled in the database, SQL
statements such as "SELECT ROWID FROM" and "UPDATE .. WHERE ROWID =
?" will work as with Informix.
To enable OID columns with PostgreSQL versions prior to version 12, the
default_with_oid PostgreSQL server parameter must be set to "on".
See Database configuration and design
tasks for more details.
SQLCA.SQLERRD[6] is partly supported: It works only for
INSERT statements. As PostgreSQL does not return the OID of the last row modified
by an UPDATE, or removed by a DELETE, this register will not
contain the OID of the last modified or deleted row. All references to
SQLCA.SQLERRD[6] should be reviewed.As a general programming pattern, consider using PRIMARY KEY columns to identify
database table rows.
ROWID", the translation can be controlled
with the following FGLPROFILE
entry:dbi.database.dsname.ifxemul.rowid = { true | false }