2.10 Known Problems

This section describes known problems and includes suggestions for correcting them when possible for Oracle Database Gateway for Sybase.

If you have any questions or concerns about the problems, contact Oracle Support Services. A current list of problems is available online. Contact your local Oracle office for information about accessing the list.

The known problems are as follows:

• Encrypted Format Login
  Oracle database no longer supports the initialization parameter DBLINK_ENCRYPT_LOGIN.
• Date Arithmetic
  Oracle Database Gateway for Sybase does not support some date arithmetic functions.
• Sybase IMAGE and TEXT Data Type
  There are restrictions when using IMAGE and TEXT data types with Oracle Database Gateway for Sybase.
• String Functions
  If you concatenate numeric literals using the "||" operator when using the gateway to query a Sybase database, the result is an arithmetic addition.
• Schema Names and PL/SQL
  If you do not prefix a Sybase database object with its schema name in a SQL statement within a PL/SQL block, an error is returned.
• Data Dictionary Views and PL/SQL
  You cannot refer to data dictionary views in SQL statements that are inside a PL/SQL block.
• Stored Procedures
  Return values of stored procedures that return result sets are incorrect.

2.10.1 Encrypted Format Login

Oracle database no longer supports the initialization parameter DBLINK_ENCRYPT_LOGIN.

Up to version 7.3, this parameter's default TRUE value prevented the password for the login user ID from being sent over the network (in the clear). Later versions automatically encrypt the password.

2.10.2 Date Arithmetic

Oracle Database Gateway for Sybase does not support some date arithmetic functions.

The following SQL expressions do not function correctly with the gateway:

date + numbernumber + datedate - numberdate1 - date2

Statements with the preceding expressions are sent to the Sybase database without any translation. Since Sybase does not support these date arithmetic functions, the statements return an error.

2.10.3 Sybase IMAGE and TEXT Data Type

There are restrictions when using IMAGE and TEXT data types with Oracle Database Gateway for Sybase.

The following restrictions apply when using IMAGE and TEXT data types:

• An unsupported SQL function cannot be used in a SQL statement that accesses a column defined as Sybase data type IMAGE or TEXT.

• You cannot use SQL*Plus to select data from a column defined as Sybase data type IMAGE or TEXT when the data is greater than 80 characters in length. Oracle recommends using Pro*C or Oracle Call Interface to access such data in a Sybase database.

• IMAGE and TEXT data cannot be read through pass-through queries.

The gateway does not support the PL/SQL function COLUMN_VALUE_LONG of the DBMS_SQL package.

See Also:

Supported SQL Syntax and Functions for more information about restrictions on SQL syntax.

2.10.4 String Functions

If you concatenate numeric literals using the "||" operator when using the gateway to query a Sybase database, the result is an arithmetic addition.

For example, the result of the following statement is 18:

SQL> SELECT 9 || 9 FROM DUAL@SYBS;

The result is 99 when using Oracle to query an Oracle database.

2.10.5 Schema Names and PL/SQL

If you do not prefix a Sybase database object with its schema name in a SQL statement within a PL/SQL block, an error is returned.

For example:

ORA-6550 PLS-201 Identifier table_name must be declared.

Change the SQL statement to include the schema name of the object.

2.10.6 Data Dictionary Views and PL/SQL

You cannot refer to data dictionary views in SQL statements that are inside a PL/SQL block.

2.10.7 Stored Procedures

Return values of stored procedures that return result sets are incorrect.