DBMS_HS_PASSTHROUGH

The DBMS_HS_PASSTHROUGH PL/SQL package allows you to send a statement directly to a non-Oracle system without being interpreted by the Oracle server. This can be useful if the non-Oracle system allows operations in statements for which there is no equivalent in Oracle.

This chapter discusses the following topics:

• DBMS_HS_PASSTHROUGH Overview

• DBMS_HS_PASSTHROUGH Operational Notes

• Summary of DBMS_HS_PASSTHROUGH Subprograms

  See Also: Oracle Database Heterogeneous Connectivity User’s Guide for more information about this package

DBMS_HS_PASSTHROUGH Overview

You can execute passthrough SQL statements directly at the non-Oracle system using the PL/SQL package DBMS_HS_PASSTHROUGH. Any statement executed with this package is executed in the same transaction as standard SQL statements.

See Also: Oracle Database Heterogeneous Connectivity User’s Guide for information about this package

DBMS_HS_PASSTHROUGH Operational Notes

The DBMS_HS_PASSTHROUGH package is a virtual package. It conceptually resides at the non-Oracle system. In reality, however, calls to this package are intercepted by Heterogeneous Services and mapped to one or more Heterogeneous Services calls. The driver, in turn, maps these Heterogeneous Services calls to the API of the non-Oracle system. The client application should invoke the procedures in the package through a database link in exactly the same way as it would invoke a non-Oracle system stored procedure. The special processing done by Heterogeneous Services is transparent to the user.

Summary of DBMS_HS_PASSTHROUGH Subprograms

This table lists the DBMS_HS_PASSTHROUGH subprograms and briefly describes them.

Table 1 DBMS_HS_PASSTHROUGH Package Subprograms

Subprogram	Description
BIND_INOUT_VARIABLE Procedure	Binds IN OUT bind variables
BIND_INOUT_VARIABLE_RAW Procedure	Binds IN OUT bind variables of datatype RAW
BIND_OUT_VARIABLE Procedure	Binds an OUT variable with a PL/SQL program variable
BIND_OUT_VARIABLE_RAW Procedure	Binds an OUT variable of datatype RAW with a PL/SQL program variable
BIND_VARIABLE Procedure	Binds an IN variable positionally with a PL/SQL program variable
BIND_VARIABLE_RAW Procedure	Binds IN variables of type RAW
CLOSE_CURSOR Procedure	Closes the cursor and releases associated memory after the SQL statement has been run at the non-Oracle system
EXECUTE_IMMEDIATE Procedure	Runs a (non-SELECT) SQL statement immediately, without bind variables
EXECUTE_NON_QUERY Function	Runs a (non-SELECT) SQL statement
FETCH_ROW Function	Fetches rows from a query
GET_VALUE Procedure	Retrieves column value from SELECT statement, or retrieves OUT bind parameters
GET_VALUE_RAW Procedure	Similar to GET_VALUE, but for datatype RAW
OPEN_CURSOR Function	Opens a cursor for running a passthrough SQL statement at the non-Oracle system
PARSE Procedure	Parses SQL statement at non-Oracle system

BIND_INOUT_VARIABLE Procedure

This procedure binds IN OUT bind variables.

Syntax

DBMS_HS_PASSTHROUGH.BIND_OUT_VARIABLE (
   c      IN  BINARY_INTEGER NOT NULL,
   p      IN  BINARY_INTEGER NULL,
   v      OUT <dty>,
   n      IN  VARCHAR2);

<dty> is either DATE, NUMBER, or VARCHAR2.

See Also: For binding OUT variables of datatype RAW, see BIND_OUT_VARIABLE_RAW Procedure.

Pragmas

Purity level defined : WNDS, RNDS

Parameters

Table 2 BIND_INOUT_VARIABLE Procedure Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened and parsed, using the routines OPEN_CURSOR and PARSE respectively.
p	Position of the bind variable in the SQL statement: Starts at 1.
v	This value is used for two purposes: - To provide the IN value before the SQL statement is run. - To determine the size of the out value.
n	(Optional) Name of the bind variable. For example, in SELECT * FROM emp WHERE ename=:ename, the position of the bind variable :ename is 1, the name is :ename. This parameter can be used if the non-Oracle system supports "named binds" instead of positional binds. Passing the position is still required.

Exceptions

Table 3 BIND_INOUT_VARIABLE Procedure Exceptions

Exception	Description
ORA-28550	The cursor passed is invalid.
ORA-28552	Procedure is not run in right order. (Did you first open the cursor and parse the SQL statement?)
ORA-28553	The position of the bind variable is out of range.
ORA-28555	A NULL value was passed for a NOT NULL parameter.

BIND_INOUT_VARIABLE_RAW Procedure

This procedure binds IN OUT bind variables of datatype RAW.

Syntax

DBMS_HS_PASSTHROUGH.BIND_INOUT_VARIABLE_RAW (
   c      IN     BINARY_INTEGER NOT NULL,
   p      IN     BINARY_INTEGER NOT NULL,
   v      IN OUT RAW,
   n      IN     VARCHAR2);

Pragmas

Purity level defined : WNDS, RNDS

Parameters

Table 4 BIND_INOUT_VARIABLE_RAW Procedure Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened and parsed using the routines OPEN_CURSOR and PARSE respectively.
p	Position of the bind variable in the SQL statement: Starts at 1.
v	This value is used for two purposes: - To provide the IN value before the SQL statement is run. - To determine the size of the out value.
n	(Optional) Name the bind variable. For example, in SELECT * FROM emp WHERE ename=:ename, the position of the bind variable :ename is 1, the name is :ename. This parameter can be used if the non-Oracle system supports "named binds" instead of positional binds. Passing the position is still required.

Exceptions

Table 5 BIND_INOUT_VARIABLE_RAW Procedure Exceptions

Exception	Description
ORA-28550	The cursor passed is invalid.
ORA-28552	Procedure is not run in right order. (Did you first open the cursor and parse the SQL statement?)
ORA-28553	The position of the bind variable is out of range.
ORA-28555	A NULL value was passed for a NOT NULL parameter.

BIND_OUT_VARIABLE Procedure

This procedure binds an OUT variable with a PL/SQL program variable.

Syntax

DBMS_HS_PASSTHROUGH.BIND_OUT_VARIABLE (
   c      IN  BINARY_INTEGER NOT NULL,
   p      IN  BINARY_INTEGER NULL,
   v      OUT <dty>,
   n      IN  VARCHAR2);

<dty> is either DATE, NUMBER, or VARCHAR2.

See Also: For binding OUT variables of datatype RAW, see BIND_OUT_VARIABLE_RAW Procedure.

Pragmas

Purity level defined : WNDS, RNDS

Parameters

Table 6 BIND_OUT_VARIABLE Procedure Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened and parsed, using the routines OPEN_CURSOR and PARSE respectively.
p	Position of the bind variable in the SQL statement: Starts at 1.
v	Variable in which the OUT bind variable stores its value. The package remembers only the “size” of the variable. After the SQL statement is run, you can use GET_VALUE to retrieve the value of the OUT parameter. The size of the retrieved value should not exceed the size of the parameter that was passed using BIND_OUT_VARIABLE.
n	(Optional) Name of the bind variable. For example, in SELECT * FROM emp WHERE ename=:ename, the position of the bind variable :ename is 1, the name is :ename. This parameter can be used if the non-Oracle system supports "named binds" instead of positional binds. Passing the position is still required.

Exceptions

Table 7 BIND_OUT_VARIABLE Procedure Exceptions

Exception	Description
ORA-28550	The cursor passed is invalid.
ORA-28552	Procedure is not run in right order. (Did you first open the cursor and parse the SQL statement?)
ORA-28553	The position of the bind variable is out of range.
ORA-28555	A NULL value was passed for a NOT NULL parameter.

BIND_OUT_VARIABLE_RAW Procedure

This procedure binds an OUT variable of datatype RAW with a PL/SQL program variable.

Syntax

DBMS_HS_PASSTHROUGH.BIND_OUT_VARIABLE_RAW (
   c     IN  BINARY_INTEGER NOT NULL,
   p     IN  BINARY_INTEGER NOT NULL,
   v     OUT RAW,
   n     IN  VARCHAR2);

Pragmas

Purity level defined : WNDS, RNDS

Parameters

Table 8 BIND_OUT_VARIABLE_RAW Procedure Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened and parsed, using the routines OPEN_CURSOR and PARSE respectively.
p	Position of the bind variable in the SQL statement: Starts at 1.
v	Variable in which the OUT bind variable stores its value. The package remembers only the “size” of the variable. After the SQL statement is run, you can use GET_VALUE to retrieve the value of the OUT parameter. The size of the retrieved value should not exceed the size of the parameter that was passed using BIND_OUT_VARIABLE_RAW.
n	(Optional) Name of the bind variable. For example, in SELECT * FROM emp WHERE ename=:ename, the position of the bind variable :ename is 1, the name is :ename. This parameter can be used if the non-Oracle system supports "named binds" instead of positional binds. Passing the position is still required.

Exceptions

Table 9 BIND_OUT_VARIABLE_RAW Procedure Exceptions

Exception	Description
ORA-28550	The cursor passed is invalid.
ORA-28552	Procedure is not run in right order. (Did you first open the cursor and parse the SQL statement?)
ORA-28553	The position of the bind variable is out of range.
ORA-28555	A NULL value was passed for a NOT NULL parameter.

BIND_VARIABLE Procedure

This procedure binds an IN variable positionally with a PL/SQL program variable.

Syntax

DBMS_HS_PASSTHROUGH.BIND_VARIABLE (
   c      IN BINARY_INTEGER NOT NULL,
   p      IN BINARY_INTEGER NOT NULL,
   v      IN <dty>,
   n      IN VARCHAR2);

<dty> is either DATE, NUMBER, or VARCHAR2.

See Also: To bind RAW variables use BIND_VARIABLE_RAW Procedure.

Pragmas

Purity level defined: WNDS, RNDS

Parameters

Table 10 BIND_VARIABLE Procedure Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened and parsed using the routines OPEN_CURSOR and PARSE respectively.
p	Position of the bind variable in the SQL statement: Starts at 1.
v	Value that must be passed to the bind variable name.
n	(Optional) Name of the bind variable. For example, in SELECT * FROM emp WHERE ename=:ename, the position of the bind variable :ename is 1, the name is :ename. This parameter can be used if the non-Oracle system supports "named binds" instead of positional binds. Passing the position is still required.

Exceptions

Table 11 BIND_VARIABLE Procedure Exceptions

Exception	Description
ORA-28550	The cursor passed is invalid.
ORA-28552	Procedure is not run in right order. (Did you first open the cursor and parse the SQL statement?)
ORA-28553	The position of the bind variable is out of range.
ORA-28555	A NULL value was passed for a NOT NULL parameter.

BIND_VARIABLE_RAW Procedure

This procedure binds IN variables of type RAW.

Syntax

DBMS_HS_PASSTHROUGH.BIND_VARIABLE_RAW (
   c    IN BINARY_INTEGER NOT NULL,
   p    IN BINARY_INTEGER NOT NULL,
   v    IN RAW,
   n    IN VARCHAR2);

Pragmas

Purity level defined : WNDS, RNDS

Parameters

Table 12 BIND_VARIABLE_RAW Procedure Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened and parsed, using the routines OPEN_CURSOR and PARSE respectively.
p	Position of the bind variable in the SQL statement: Starts at 1.
v	Value that must be passed to the bind variable.
n	(Optional) Name of the bind variable. For example, in SELECT * FROM emp WHERE ename=:ename, the position of the bind variable :ename is 1, the name is :ename. This parameter can be used if the non-Oracle system supports "named binds" instead of positional binds. Passing the position is still required.

Exceptions

Table 13 BIND_VARIABLE_RAW Procedure Exceptions

Exception	Description
ORA-28550	The cursor passed is invalid.
ORA-28552	Procedure is not run in right order. (Did you first open the cursor and parse the SQL statement?)
ORA-28553	The position of the bind variable is out of range.
ORA-28555	A NULL value was passed for a NOT NULL parameter.

CLOSE_CURSOR Procedure

This function closes the cursor and releases associated memory after the SQL statement has been run at the non-Oracle system. If the cursor was not open, then the operation is a “no operation”.

Syntax

DBMS_HS_PASSTHROUGH.CLOSE_CURSOR (
   c IN BINARY_INTEGER NOT NULL);

Pragmas

Purity level defined : WNDS, RNDS

Parameters

Table 14 CLOSE_CURSOR Procedure Parameters

Parameter	Description
c	Cursor to be released.

Exceptions

Table 15 CLOSE_CURSOR Procedure Exceptions

Exception	Description
ORA-28555	A NULL value was passed for a NOT NULL parameter.

EXECUTE_IMMEDIATE Procedure

This function runs a SQL statement immediately. Any valid SQL command except SELECT can be run immediately.

The statement must not contain any bind variables. The statement is passed in as a VARCHAR2 in the argument. Internally the SQL statement is run using the PASSTHROUGH SQL protocol sequence of OPEN_CURSOR, PARSE, EXECUTE_NON_QUERY, CLOSE_CURSOR.

Syntax

DBMS_HS_PASSTHROUGH.EXECUTE_IMMEDIATE (
   s IN VARCHAR2 NOT NULL)
RETURN BINARY_INTEGER;

Parameters

Table 16 EXECUTE_IMMEDIATE Procedure Parameters

Parameter	Description
s	VARCHAR2 variable with the statement to be executed immediately.

Return Values

The number of rows affected by the execution of the SQL statement.

Exceptions

Table 17 EXECUTE_IMMEDIATE Procedure Exceptions

Exception	Description
ORA-28551	SQL statement is invalid.
ORA-28554	Max open cursors.
ORA-28555	A NULL value was passed for a NOT NULL parameter.

EXECUTE_NON_QUERY Function

This function runs a SQL statement. The SQL statement cannot be a SELECT statement. A cursor has to be open and the SQL statement has to be parsed before the SQL statement can be run.

Syntax

DBMS_HS_PASSTHROUGH.EXECUTE_NON_QUERY (
   c IN BINARY_INTEGER NOT NULL)
  RETURN BINARY_INTEGER;

Parameters

Table 18 EXECUTE_NON_QUERY Function Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened and parsed, using the routines OPEN_CURSOR and PARSE respectively.

Return Values

The number of rows affected by the SQL statement in the non-Oracle system

Exceptions

Table 19 EXECUTE_NON_QUERY Function Exceptions

Exception	Description
ORA-28550	The cursor passed is invalid.
ORA-28552	Procedure is not run in right order. (Did you first open the cursor and parse the SQL statement?)
ORA-28555	A NULL value was passed for a NOT NULL parameter.

FETCH_ROW Function

This function fetches rows from a result set.

The result set is defined with a SQL SELECT statement. When there are no more rows to be fetched, the exception NO_DATA_FOUND is raised. Before the rows can be fetched, a cursor has to be opened, and the SQL statement has to be parsed.

Syntax

DBMS_HS_PASSTHROUGH.FETCH_ROW (
   c   IN BINARY_INTEGER NOT NULL,
   f   IN BOOLEAN)
  RETURN BINARY_INTEGER;

Pragmas

Purity level defined : WNDS

Parameters

Table 20 FETCH_ROW Function Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened and parsed, using the routines OPEN_CURSOR and PARSE respectively.
first	(Optional) Reexecutes SELECT statement. Possible values: - TRUE: reexecute SELECT statement. - FALSE: fetch the next row, or if run for the first time, then execute and fetch rows (default).

Return Values

The returns the number of rows fetched. The function returns “0” if the last row was already fetched.

Exceptions

Table 21 FETCH_ROW Function Exceptions

Exception	Description
ORA-28550	The cursor passed is invalid.
ORA-28552	Procedure is not run in right order. (Did you first open the cursor and parse the SQL statement?)
ORA-28555	A NULL value was passed for a NOT NULL parameter.

GET_VALUE Procedure

This procedure has two purposes: it retrieves the select list items of SELECT statements after a row has been fetched, and it retrieves the OUT bind values, after the SQL statement has been run.

Syntax

DBMS_HS_PASSTHROUGH.GET_VALUE (
   c      IN  BINARY_INTEGER NOT NULL,
   p    IN  BINARY_INTEGER NOT NULL,
   v    OUT <dty>);

<dty> is either DATE, NUMBER, or VARCHAR2.

See Also: For retrieving values of datatype RAW, see GET_VALUE_RAW Procedure.

Pragmas

Purity level defined : WNDS

Parameters

Table 22 GET_VALUE Procedure Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened and parsed, using the routines OPEN_CURSOR and PARSE respectively.
p	Position of the bind variable or select list item in the SQL statement: Starts at 1.
v	Variable in which the OUT bind variable or select list item stores its value.

Exceptions

Table 23 GET_VALUE Procedure Exceptions

Exception	Description
ORA-1403	Returns NO_DATA_FOUND exception when running the GET_VALUE after the last row was fetched (that is, FETCH_ROW returned “0”).
ORA-28550	The cursor passed is invalid.
ORA-28552	Procedure is not run in right order. (Did you first open the cursor and parse the SQL statement?)
ORA-28553	The position of the bind variable is out of range.
ORA-28555	A NULL value was passed for a NOT NULL parameter.

GET_VALUE_RAW Procedure

This procedure is similar to GET_VALUE, but for datatype RAW.

Syntax

DBMS_HS_PASSTHROUGH.GET_VALUE_RAW (
   c    IN  BINARY_INTEGER NOT NULL,
   p    IN  BINARY_INTEGER NOT NULL,
   v    OUT RAW);

Pragmas

Purity level defined : WNDS

Parameters

Table 24 GET_VALUE_RAW Procedure Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened and parsed, using the routines OPEN_CURSOR and PARSE respectively.
p	Position of the bind variable or select list item in the SQL statement: Starts at 1.
v	Variable in which the OUT bind variable or select list item stores its value.

Exceptions

Table 25 GET_VALUE_RAW Procedure Exceptions

Exception	Description
ORA-1403	Returns NO_DATA_FOUND exception when running the GET_VALUE after the last row was fetched (that is, FETCH_ROW returned “0”).
ORA-28550	The cursor passed is invalid.
ORA-28552	Procedure is not run in right order. (Did you first open the cursor and parse the SQL statement?)
ORA-28553	The position of the bind variable is out of range.
ORA-28555	A NULL value was passed for a NOT NULL parameter.

OPEN_CURSOR Function

This function opens a cursor for running a passthrough SQL statement at the non-Oracle system. This function must be called for any type of SQL statement.

The function returns a cursor, which must be used in subsequent calls. This call allocates memory. To deallocate the associated memory, call the procedure CLOSE_CURSOR.

Syntax

DBMS_HS_PASSTHROUGH.OPEN_CURSOR
  RETURN BINARY_INTEGER;

Pragmas

Purity level defined : WNDS, RNDS

Return Values

The cursor to be used on subsequent procedure and function calls.

Exceptions

Table 26 OPEN_CURSOR Function Exceptions

Exception	Description
ORA-28554	Maximum number of open cursor has been exceeded. Increase Heterogeneous Services’ OPEN_CURSORS initialization parameter.

PARSE Procedure

This procedure parses an SQL statement at a non-Oracle system.

Syntax

DBMS_HS_PASSTHROUGH.PARSE (
   c       IN  BINARY_INTEGER NOT NULL,
   stmt    IN  VARCHAR2 NOT NULL);

Pragmas

Purity level defined : WNDS, RNDS

Parameters

Table 27 PARSE Procedure Parameters

Parameter	Description
c	Cursor associated with the passthrough SQL statement. Cursor must be opened using function OPEN_CURSOR.
stmt	Statement to be parsed.

Exceptions

Table 28 PARSE Procedure Exceptions

Exception	Description
ORA-28550	The cursor passed is invalid.
ORA-28551	SQL statement is illegal.
ORA-28555	A NULL value was passed for a NOT NULL parameter.