B Supported SQL Syntax and Functions

This appendix contains the following sections:

See Also:

Oracle Database SQL Reference for detailed descriptions of keywords, parameters, and options and the Adabas documentation for details of executing SQL statements in a transaction.

Supported SQL Statements

With a few exceptions, the gateway provides full support for Oracle DELETE, INSERT, SELECT, and UPDATE statements.

The gateway does not support Oracle data definition language (DDL) statements. No form of the Oracle ALTER, CREATE, DROP, GRANT, or TRUNCATE statements can be used. Instead, for ALTER, CREATE, DROP, and GRANT statements, use the pass-through feature of the gateway if you need to use DDL statements against the Adabas database.

Note:

TRUNCATE cannot be used in a pass-through statement.

DELETE

The DELETE statement is fully supported. However, only Oracle functions supported by Adabas can be used.

See Also:

"Functions Supported by Adabas" for a list of supported functions.

INSERT

The INSERT statement is fully supported. However, only Oracle functions supported by Adabas can be used.

See Also:

"Functions Supported by Adabas" for a list of supported functions.

SELECT

The SELECT statement is fully supported, with these exceptions:

  • CONNECT BY condition

  • NOWAIT

  • START WITH condition

  • WHERE CURRENT OF

UPDATE

The UPDATE statement is fully supported. However, only Oracle functions supported by Adabas can be used. Also, you cannot have SQL statements in the subquery that refer to the same table name in the outer query. Subqueries are not supported in the SET clause.

See Also:

"Functions Supported by Adabas" for a list of supported functions.

Oracle Functions

All functions are evaluated by the Adabas database after the gateway has converted them to Adabas SQL.

Functions Not Supported by Adabas

Oracle SQL functions with no equivalent function in Adabas are not supported in DELETE, INSERT, or UPDATE statements, but are evaluated by the Oracle database server if the statement is a SELECT statement. That is, the Oracle database server performs post-processing of SELECT statements sent to the gateway.

If an unsupported function is used in a DELETE, INSERT, or UPDATE, statement, the following Oracle error occurs:

ORA-02070: database db_link_name does not support function in this context

See Also:

Oracle Database Error Messages for more information on error messages.

Functions Supported by Adabas

The gateway translates the following Oracle database server functions in SQL statements to their equivalent Adabas functions:

Arithmetic Operators

The following table specifies the arithmetic operators.

Oracle Adabas
+ +
- -
* *
/ /

Comparison Operators

The following table specifies the comparison operators.

Oracle Adabas
= =
> >
< <
>= >=
<= <=
<>, !=, ^= <>, !=
IS NOT NULL IS NOT NULL
IS NULL IS NULL

Group Functions

The following table specifies the group functions.

Oracle Adabas
AVG AVG
COUNT COUNT
MAX MAX
MIN MIN
SUM SUM

String Functions

The following table specifies the string functions.

Oracle Adabas
|| + (expression1 + expression2)
ASCII ASCII
CHR CHAR
INSTR CHARINDEX
LENGTH CHAR_LENGTH
LOWER LOWER
SUBSTR (second argument cannot be a negative number) SUBSTRING
UPPER UPPER

Other Functions

The following table specifies other functions.

Oracle Adabas
ABS ABS
CEIL CEILING
COS COS
EXP EXP
FLOOR FLOOR
LN LOG
LOG LOG10
MOD %
NVL IS NULL
POWER POWER
ROUND ROUND
SIN SIN
SQRT SQRT
TAN TAN