Interface Subprograms

Several Natural and non-Natural subprograms are available to provide you with internal information from Natural for Db2 or specific functions for which no equivalent Natural statements exist.

This section covers the following topics:

Natural Subprograms
DB2SERV Interface

Natural Subprograms

The following Natural subprograms are provided:

Subprogram	Function
`NDBCONV`	Sets or resets conversational mode 2.
`NDBDBRM`	Checks whether a Natural program contains SQL access and whether it has been modified for static execution.
`NDBDBR2`	Checks whether a Natural program contains SQL access and whether it has been modified for static execution.
`NDBDBR3`	Checks whether a Natural program contains SQL access, whether it has been modified for static execution, and whether it can be generated as static.
`NDBDBRZ`	Checks whether a Natural program contains SQL access, whether it has been modified for NDZ static execution, and whether it can be generated as static.
`NDBERR`	Provides diagnostic information on the most recently executed SQL call.
`NDBISQL`	Executes SQL statements in dynamic mode.
`NDBISQLD`	Executes SQL statements in dynamic mode, using dynamic variables.
`NDBNOERR`	Suppresses normal Natural error handling.
`NDBNROW`	Obtains the number of rows affected by a Natural SQL statement.
`NDBSTMP`	Provides a Db2 `TIMESTAMP` column as an alphanumeric field and vice versa.

All these subprograms are provided in the Natural system library SYSDB2 and the Natural library SYSTEM on the system file FNAT.

In addition, the Natural library SYSTEM in the FNAT system file contains the subprogram DBTLIB2N and the subroutine DBDL219S. They are used by NDBDBRM and NDBDBR2. The corresponding parameters must be defined in a DEFINE DATA statement.

The Natural subprograms NDBDBRM, NDBDBR2 and NDBDBR3 allow the optional specification of the database ID, file number, password and cipher code of the library file containing the program to be examined.

If these parameters are not specified, either the actual FNAT file or the FUSER file is used to locate the program to be examined depending on whether the library name begins with "SYS" or not.

Programs invoking NDBDBRM, NDBDBR2 or NDBDBR3 without these parameters will also work like before this change as the added parameters are declared as optional.

For detailed information on these subprograms, follow the links shown in the table above and read the description of the call format and of the parameters in the text object provided with the subprogram (subprogram-nameT).

Invoking Subprograms from within a Natural Program

Natural subprograms are invoked with the Natural CALLNAT statement.
Non-Natural subprograms are invoked with the Natural CALL statement.

NDBCONV Subprogram

The Natural subprogram NDBCONV is used to either set or reset the conversational mode 2 in CICS environments. Conversational mode 2 means that update transactions are spawned across terminal I/Os until either a COMMIT or ROLLBACK has been issued (Caution Db2 and CICS resources are kept across terminal I/Os!). This means conversational mode 2 has the same effect as the Natural profile parameter PSEUDO=OFF, except that the conversational mode is entered after an Db2 update statement (UPDATE, DELETE, INSERT) and left again after a COMMIT or ROLLBACK, while PSEUDO=OFF causes conversational mode for the total Natural session.

A sample program called CALLCONV is provided in library SYSDB2; it demonstrates how to invoke NDBCONV. A description of the call format and of the parameters is provided in the text object NDBCONVT.

The calling Natural program must use the following syntax:

CALLNAT 'NDBCONV' #CONVERS #RESPONSE

The various parameters are described in the following table:

Parameter	Format/Length	Explanation
`#CONVERS`	I1	Contains the desired conversational mode (input)
`#RESPONSE`	I4	Contains the response of `NDBCONV` (output)

The #CONVERS parameter can contain the following values:

Code	Explanation
`0`	The conversational mode 2 has to be reset.
`1`	The conversational mode 2 has to be set.

The #RESPONSE parameter can contain the following response codes:

Code	Explanation
`0`	The conversational mode 2 has been successfully set or reset.
`-1`	The specified value of `#CONVERS` is invalid, the conversational mode has not been changed.
`-2`	`NDBCONV` is called in a environment, which is not a CICS environment, where the conversational mode 2 is not supported.

NDBDBRM Subprogram

The Natural subprogram NDBDBRM is used to check whether a Natural program contains SQL access and whether it has been modified for static execution. It is also used to obtain the corresponding DBRM (database request module) name from the header of a Natural program generated as static (see also Preparing Programs for Static Execution).

A sample program called CALLDBRM is provided on the installation medium; it demonstrates how to invoke NDBDBRM. A description of the call format and of the parameters is provided in the text object NDBDBRMT.

The calling Natural program must use the following syntax:

CALLNAT 'NDBDBRM' #LIB #MEM #DBRM #RESP #DBID #FILENR #PASSWORD #CIPHER

The various parameters are described in the following table:

Parameter	Format/Length	Explanation
`#LIB`	A8	Contains the name of the library of the program to be checked.
`#MEM`	A8	Contains the name of the program (member) to be checked.
`#DBRM`	A8	Returns the DBRM name.
`#RESP`	I2	Returns a response code. The possible codes are listed below.
`#DBID`	N5	Optional. Database ID of library file.
`#FILENR`	N5	Optional. File number of library file.
`#PASSWORD`	A8	Optional. Password of library file.
`#CIPHER`	N8	Optional. Cipher code of library file.

The #RESP parameter can contain the following values:

Code	Explanation
`0`	The member `#MEM` in library `#LIB` has SQL access; it is static if `#DBRM` contains a value.
`-1`	The member `#MEM` in library `#LIB` has no SQL access.
`-2`	The member `#MEM` in library `#LIB` does not exist.
`-3`	No library name has been specified.
`-4`	No member name has been specified.
`-5`	The library name must start with a letter.
`>-5`	Further negative response codes correspond to error numbers of Natural error messages.
`>0`	Positive response codes correspond to error numbers of Natural Security messages.

NDBDBR2 Subprogram

The Natural subprogram NDBDBR2 is used to check whether a Natural program contains SQL access and whether it has been modified for static execution. It is also used to obtain the corresponding DBRM (database request module) name from the header of a Natural program generated as static (see also Preparing Programs for Static Execution) and the time stamp generated by the precompiler.

A sample program called CALLDBR2 is provided on the installation medium; it demonstrates how to invoke NDBDBR2. A description of the call format and of the parameters is provided in the text object NDBDBR2T.

The calling Natural program must use the following syntax:

CALLNAT 'NDBDBR2' #LIB #MEM #DBRM #TIMESTAMP #PCUSER #PCRELLEV #ISOLLEVL #DATEFORM #TIMEFORM #RESP #DBID #FILENR #PASSWORD #CIPHER

The various parameters are described in the following table:

Parameter	Format/Length	Explanation
`#LIB`	A8	Contains the name of the library of the program to be checked.
`#MEM`	A8	Contains the name of the program (member) to be checked.
`#DBRM`	A8	Returns the DBRM name.
`#TIMESTAMP`	B8	Consistency token generated by precompiler.
`#PCUSER`	A8	Unsupported parameter; retained for compatibility reasons. only.
`#PCRELLEV`	A1	Unsupported parameter; retained for compatibility reasons only.
`#ISOLLEVL`	A1	Unsupported parameter; retained for compatibility reasons only.
`#DATEFORM`	A1	Unsupported parameter; retained for compatibility reasons only.
`#TIMEFORM`	A1	Unsupported parameter; retained for compatibility reasons only.
`#RESP`	I2	Returns a response code. The possible codes are listed below.
`#DBID`	N5	Optional. Database ID of library file.
`#FILENR`	N5	Optional. File number of library file.
`#PASSWORD`	A8	Optional. Password of library file.
`#CIPHER`	N8	Optional. Cipher code of library file.

The #RESP parameter can contain the following values:

Code	Explanation
`0`	The member `#MEM` in library `#LIB` has SQL access; it is static if `#DBRM` contains a value.
`-1`	The member `#MEM` in library `#LIB` has no SQL access.
`-2`	The member `#MEM` in library `#LIB` does not exist.
`-3`	No library name has been specified.
`-4`	No member name has been specified.
`-5`	The library name must start with a letter.
`>-5`	Further negative response codes correspond to error numbers of Natural error messages.
`>0`	Positive response codes correspond to error numbers of Natural Security messages.

NDBDBR3 Subprogram

The Natural subprogram NDBDBR3is used to check whether a Natural program contains SQL access (#RESP 0), whether the Natural program contains solely SQL statements, which are dynamically executable (#RESP 0, #DBRM ‘*DYNAMIC’) and whether it has been modified for static execution (#RESP 0, #DBRM dbrmname). It is also used to obtain the corresponding DBRM (database request module) name from the header of a Natural program generated as static (see also Preparing Programs for Static Execution) and the time stamp generated by the precompiler.

A sample program called CALLDBR3 is provided on the installation medium; it demonstrates how to invoke NDBDBR3. A description of the call format and of the parameters is provided in the text object NDBDBR3T.

The calling Natural program must use the following syntax:

CALLNAT 'NDBDBR3' #LIB #MEM #DBRM #TIMESTAMP #PCUSER #PCRELLEV #ISOLLEVL #DATEFORM #TIMEFORM #RESP #DBID #FILENR #PASSWORD #CIPHER

The various parameters are described in the following table:

Parameter	Format/Length	Explanation
`#LIB`	A8	Contains the name of the library of the program to be checked.
`#MEM`	A8	Contains the name of the program (member) to be checked.
`#DBRM`	A8	Returns the DBRM name. Space, if program has SQL access, `*DYNAMIC`, if program contains only dynamically executable SQL, DBRM name, if program has been generated static.
`#TIMESTAMP`	B8	Consistency token generated by precompiler.
`#PCUSER`	A8	Unsupported parameter; retained for compatibility reasons only.
`#PCRELLEV`	A1	Unsupported parameter; retained for compatibility reasons only.
`#ISOLLEVL`	A1	Unsupported parameter; retained for compatibility reasons only.
`#DATEFORM`	A1	Unsupported parameter; retained for compatibility reasons only.
`#TIMEFORM`	A1	Unsupported parameter; retained for compatibility reasons only.
`#RESP`	I2	Returns a response code. The possible codes are listed below.
`#DBID`	N5	Optional. Database ID of library file.
`#FILENR`	N5	Optional. File number of library file.
`#PASSWORD`	A8	Optional. Password of library file.
`#CIPHER`	N8	Optional. Cipher code of library file.

The #RESP parameter can contain the following values:

Code	Explanation
`0`	The member `#MEM` in library `#LIB` has SQL access; it is static if `#DBRM` contains a value other than space and `*DYNAMIC`.
`-1`	The member `#MEM` in library `#LIB` has no SQL access.
`-2`	The member `#MEM` in library `#LIB` does not exist.
`-3`	No library name has been specified.
`-4`	No member name has been specified.
`-5`	The library name must start with a letter.
`>-5`	Further negative response codes correspond to error numbers of Natural error messages.
`>0`	Positive response codes correspond to error numbers of Natural Security messages.

NDBDBRZ Subprogram

The Natural subprogram NDBDBRZ is used to check whether a Natural program contains SQL access (#RESP 0), whether the Natural program contains solely SQL statements, which are dynamically executable (#RESP 0, #SQLJPROF ‘*DYNAMIC’) and whether it has been modified for NDZ static execution (#RESP 0, #SQLJPROF SQLJ profile name). It is also used to obtain the corresponding SQLJ profile name from the header of a Natural program generated as static (see also Preparing Programs for Static Execution).

A sample program called CALLDBRZ is provided on the installation medium and it demonstrates how to invoke NDBDBRZ. A description of the call format and of the parameters is provided in the text object NDBDBRZT.

The calling Natural program must use the following syntax:

CALLNAT 'NDBDBRZ' #LIB #MEM #SQLJPROF #RESP #DBID #FILENR #PASSWORD #CIPHER

The various parameters are described in the following table:

Parameter	Format/Length	Explanation
`#LIB`	A8	Contains the name of the library of the program to be checked.
`#MEM`	A8	Contains the name of the program (member) to be checked.
`#SQLJPROF`	A8	Returns the SQLJ profile name. Space, if program has SQL access, `*DYNAMIC`, if program contains only dynamically executable SQL, SQLJ profile name, if program has been generated static.
`#RESP`	I2	Returns a response code. The possible codes are listed below.
`#DBID`	N5	Optional. Database ID of library file.
`#FILENR`	N5	Optional. File number of library file.
`#PASSWORD`	A8	Optional. Password of library file.
`#CIPHER`	N8	Optional. Cipher code of library file.

The #RESP parameter can contain the following values:

Code	Explanation
`0`	The member `#MEM` in library `#LIB` has SQL access; it is static if `#DBRM` contains a value other than space and `*DYNAMIC`.
`-1`	The member `#MEM` in library `#LIB` has no SQL access.
`-2`	The member `#MEM` in library `#LIB` does not exist.
`-3`	No library name has been specified.
`-4`	No member name has been specified.
`-5`	The library name must start with a letter.
`>-5`	Further negative response codes correspond to error numbers of Natural error messages.
`>0`	Positive response codes correspond to error numbers of Natural Security messages.

NDBERR Subprogram

The Natural subprogram NDBERR replaces Function E of the DB2SERV interface, which is still provided but no longer documented. It provides diagnostic information on the most recent SQL call. It also returns the database type which returned the error. NDBERR is typically called if a database call returns a non-zero SQLCODE (which means a NAT3700 error).

A sample program called CALLERR is provided on the installation medium; it demonstrates how to invoke NDBERR. A description of the call format and of the parameters is provided in the text object NDBERRT.

The calling Natural program must use the following syntax:

CALLNAT 'NDBERR' #SQLCODE #SQLSTATE #SQLCA #DBTYPE

The various parameters are described in the following table:

Parameter	Format/Length	Explanation
`#SQLCODE`	I4	Returns the SQL return code.
`#SQLSTATE`	A5	Returns a return code for the output of the most recently executed SQL statement.
`#SQLCA`	A136	Returns the SQL communication area of the most recent Db2 access.
`#DBTYPE`	B1	Returns the identifier (in hexadecimal format) for the currently used database (where `X'02'` identifies Db2).

NDBISQL Subprogram

The Natural subprogram NDBISQL is used to execute SQL statements in dynamic mode. The SELECT statement and all SQL statements which can be prepared dynamically (according to the Db2 literature by IBM) can be passed to NDBISQL.

A sample program called CALLISQL is provided on the installation medium; it demonstrates how to invoke NDBISQL. A description of the call format and of the parameters is provided in the text object NDBISQLT.

The calling Natural program must use the following syntax:

CALLNAT 'NDBISQL'#FUNCTION #TEXT-LEN #TEXT (*) #SQLCA #RESPONSE #WORK-LEN #WORK (*)

The various parameters are described in the following table:

Parameter	Format/Length	Explanation
`#FUNCTION`	A8	For valid functions, see below.
`#TEXT-LEN`	I2	Length of the SQL statement or of the buffer for the return area.
`#TEXT`	A1(1:V)	Contains the SQL statement (`EXECUTE`) or receives a data row (`FETCH`).
`#SQLCA`	A136	Contains the SQLCA.
`#RESPONSE`	I4	Returns a response code.
`#WORK-LEN`	I2	Length of the workarea specified by `#WORK` (optional).
`#WORK`	A1(1:V)	Workarea used to hold SQLDA/SQLVAR and auxiliary fields across calls (optional).
`#DBTYPE`	I2	Database type (optional).
		`0`	Default
		`2`	DB2
		`4`	CNX

Valid functions for the #FUNCTION parameter are:

Function	Parameter	Explanation
`CLOSE`		Closes the cursor for the `SELECT` statement.
`EXECUTE`	#TEXT-LEN #TEXT (*)	Executes the SQL statement. Contains the length of the statement. Contains the SQL statement. The first two characters must be blank.
`FETCH`	#TEXT-LEN #TEXT (*)	Returns a record from the `SELECT` statement. Size of `#TEXT` (in bytes). Buffer for the record.
`TITLE`	`#TEXT-LEN` `#TEXT (*)`	Returns the header for the `SELECT` statement. Size of `#TEXT` (in bytes); receives the length of the header (= length of the record). Buffer for the header line.

The #RESPONSE parameter can contain the following response codes:

Code	Function	Explanation
`5`	`EXECUTE`	The statement is a `SELECT` statement.
`6`	`TITLE`, `FETCH`	Data are truncated; only set on first `TITLE` or `FETCH` call.
`100`	`FETCH`	No record / end of data.
`-2`		Unsupported data type (for example, `GRAPHIC`).
`-3`	`TITLE`, `FETCH`	No cursor open; probably invalid call sequence or statement other than `SELECT`.
`-4`		Too many columns in result table.
`-5`		SQLCODE from call.
`-6`		Version mismatch.
`-7`		Invalid function.
`-8`		Error from SQL call.
`-9`		Workarea invalid (possibly relocation).
`-10`		Interface not available.
`-11`	`EXECUTE`	First two bytes of statement not blank.

Call Sequence

The first call must be an EXECUTE call. NDBISQL has a fixed SQLDA AREA holding space for 50 columns. If this area is too small for a particular SELECT it is possible to supply an optional work area on the calls to NDBISQL by specifying #WORK-LEN (I2) and #WORK(A1/1:V).

This workarea is used to hold the SQLDA and temporary work fields like null indicators and auxiliary fields for numeric columns. Calculate 16 bytes for SQLDA header and 44 bytes for each result column and 2 bytes null indicator for each column and place for each numeric column, when supplying #WORK-LEN and #WORK(*) during NDBISQL calls. If these optional parameters are specified on an EXECUTE call they have also to be specified on any following call.

If the statement is a SELECT statement (that is, response code 5 is returned), any sequence of TITLE and FETCH calls can be used to retrieve the data. A response code of 100 indicates the end of the data.

The cursor must be closed with a CLOSE call.

Function code EXECUTE implicitly closes a cursor which has been opened by a previous EXECUTE call for a SELECT statement.

In TP environments, no terminal I/O can be performed between an EXECUTE call and any TITLE, FETCH or CLOSE call that refers to the same statement.

NDBISQLD Subprogram

The Natural subprogram NDBISQLD is used to execute SQL statements in dynamic mode. The SELECT statement and all SQL statements which can be prepared dynamically (according to the Db2 literature by IBM) can be passed to NDBISQLD.

A sample program called CALISQLD is provided on the installation medium. It demonstrates how to invoke NDBISQLD. A description of the call format and of the parameters is provided in the text object ISQLDT.

The calling Natural program must use the following syntax:

CALLNAT 'NDBISQLD'#FUNCTION #TEXT #SQLCA #RESPONSE #WORK #DBTYPE

The various parameters are described in the following table:

Parameter	Format/Length	Explanation
`#FUNCTION`	A8	For valid functions, see below.
`#TEXT`	A DYNAMIC	Contains the SQL statement (`EXECUTE`) or receives the data row (`FETCH`).
`#SQLCA`	A136	Contains the SQLCA.
`#RESPONSE`	I4	Returns a response code.
`#WORK`	A DYNAMIC	Workarea used to hold SQLDA/SQLVAR and auxiliary fields across calls (optional). If specified, `#WORK` has to be sized large enough to hold all auxiliary fields (SQLDA) for the SQL request.
`#DBTYPE`	I2	Database type (optional).
		`0`	Default
		`2`	DB2
		`4`	CNX

Valid functions for the #FUNCTION parameter are:

Function	Parameter	Explanation
`CLOSE`	-	Closes the cursor for the `SELECT` statement.
`EXECUTE`	`#TEXT`	Executes the SQL statement. Contains the SQL statement. The first four characters must be blank.
`FETCH`	`#TEXT`	Returns a row from the `SELECT` statement. `#TEXT` has to be sized large enough to hold the row of the result set created by the `SELECT` statement. After `FETCH`, the `*LENGTH(#TEXT)` is reduced to the exact size of the row.
`TITLE`	`#TEXT`	Returns the header literals for the `SELECT` statement. `#TEXT` has to be sized large enough to hold the row of the result set created by the `SELECT` statement.

The #RESPONSE parameter can contain the following response codes:

Code	Function	Explanation
`5`	`EXECUTE`	The statement is a `SELECT` statement.
`6`	`TITLE`, `FETCH`	Data are truncated; only set on first `TITLE` or `FETCH` call.
`100`	`FETCH`	No record/end of data.
`-2`	-	Unsupported data type (for example, `GRAPHIC`).
`-3`	`TITLE`, `FETCH`	No cursor open. Probably invalid call sequence or statement other than `SELECT`.
`-4`	-	Too many columns in result table.
`-5`	-	SQLCODE from call.
`-6`	-	Version mismatch.
`-7`	-	Invalid function.
`-8`	-	Error from SQL call.
`-9`	-	Workarea invalid (possibly relocation).
`-10`	-	Interface not available.
`-11`	`EXECUTE`	First two bytes of statement not blank.

Call Sequence

The first call must be an EXECUTE call. NDBISQLD has a fixed SQLDA AREA, holding space for 50 columns. If this area is too small for a particular SELECT, it is possible to supply an optional work area on the calls to NDBISQLD by #WORK(A)DYNAMIC.

This workarea is used to hold the SQLDA and temporary work fields like null indicators and auxiliary fields for numeric columns. Calculate 16 bytes for SQLDA header and 44 bytes for each result column and 2 bytes null indicator for each column and place for each numeric column, when supplying #WORK(A)DYNAMIC during NDBISQLD calls. If these optional parameters are specified on an EXECUTE call, they have also to be specified on any following call.

If the statement is a SELECT statement (that is, response code 5 is returned), any sequence of TITLE and FETCH calls can be used to retrieve the data. A response code of 100 indicates the end of the data.

The cursor must be closed with a CLOSE call.

Function code EXECUTE implicitly closes a cursor which has been opened by a previous EXECUTE call for a SELECT statement.

In TP environments, no terminal I/O can be performed between an EXECUTE call and any TITLE, FETCH or CLOSE call that refers to the same statement.

NDBNOERR Subprogram

The Natural subprogram NDBNOERR is used to suppress Natural NAT3700 errors caused by the next SQL call. This allows a program controlled continuation if an SQL statement produces a non-zero SQLCODE. After the SQL call has been performed, NDBERR is used to investigate the SQLCODE.

A sample program called CALLNOER is provided on the installation medium; it demonstrates how to invoke NDBNOERR. A description of the call format and of the parameters is provided in the text object NDBNOERT.

The calling Natural program must use the following syntax:

CALLNAT 'NDBNOERR'

There are no parameters provided with this subprogram.

Note:
Only NAT3700 errors (that is, non-zero SQL response codes) are suppressed, and also only errors caused by the next following SQL call.

Restrictions with Database Loops

If NDBNOERR is called before a statement that initiates a database loop and an initialization error occurs, no processing loop will be initiated, unless a IF NO RECORDS FOUND clause has been specified.
If NDBNOERR is called within a database loop, it does not apply to the processing loop itself, but only to the SQL statement subsequently executed inside this loop.

NDBNROW Subprogram

The Natural subprogram NDBNROW is used to obtain the number of rows affected by the Natural SQL statements Searched UPDATE, Searched DELETE, and INSERT. The number of rows affected is read from the SQL communication area (SQLCA). A positive value represents the number of affected rows, whereas a value of minus one (-1) indicates that all rows of a table in a segmented tablespace have been deleted; see also the Natural system variable *NUMBER as described in the Natural System Variables documentation.

A sample program called CALLNROW is provided on the installation medium; it demonstrates how to invoke NDBNROW. A description of the call format and of the parameters is provided in the text object NDBNROWT.

The calling Natural program must use the following syntax:

CALLNAT 'NDBNROW' #NUMBER

The parameter #NUMBER (I4) contains the number of affected rows.

NDBSTMP Subprogram

For Db2, Natural provides a TIMESTAMP column as an alphanumeric field (A26) of the format YYYY-MM-DD-HH.MM.SS.MMMMMM.

Since Natural does not yet support computation with such fields, the Natural subprogram NDBSTMP is provided to enable this kind of functionality. It converts Natural time variables to Db2 time stamps and vice versa and performs Db2 time stamp arithmetics.

A sample program called CALLSTMP is provided on the installation medium; it demonstrates how to invoke NDBSTMP. A description of the call format and of the parameters is provided in the text object NDBSTMPT.

The functions available are:

Code	Explanation
`ADD`	Adds time units (labeled durations) to a given Db2 time stamp and returns a Natural time variable and a new Db2 time stamp.
`CNT2`	Converts a Natural time variable (format T) into a Db2 time stamp (column type `TIMESTAMP`) and labeled durations.
`C2TN`	Converts a Db2 time stamp (column type `TIMESTAMP`) into a Natural time variable (format T) and labeled durations.
`DIFF`	Builds the difference between two given Db2 time stamps and returns labeled durations.
`GEN`	Generates a Db2 time stamp from the current date and time values of the Natural system variable `*TIMX` and returns a new Db2 time stamp.
`SUB`	Subtracts labeled durations from a given Db2 time stamp and returns a Natural time variable and a new Db2 time stamp.
`TEST`	Tests a given Db2 time stamp for valid format and returns `TRUE` or `FALSE`.

Note:
Labeled durations are units of year, month, day, hour, minute, second and microsecond.

DB2SERV Interface

DB2SERV is an Assembler program entry point which can be called from within a Natural program.

DB2SERV performs either of the following functions:

Function D
Function P

Function D, which performs the SQL statement EXECUTE IMMEDIATE.
Function P, invokes an Assembler module named NDBPLAN.

The parameter or variable values returned by each of these functions are checked for their format, length, and number.

Function D

Function D performs the SQL statement EXECUTE IMMEDIATE. This allows SQL statements to be issued from within a Natural program.

The SQL statement string that follows the EXECUTE IMMEDIATE statement must be assigned to the Natural program variable STMT. It must contain valid SQL statements allowed with the EXECUTE IMMEDIATE statement as described in the relevant IBM literature. Examples can be found below and in the demonstration programs DEM2* in the Natural system library SYSDB2.

Note:
The conditions that apply to issuing the Natural END TRANSACTION or BACKOUT TRANSACTION statements also apply when issuing the SQL COMMIT or ROLLBACK statements.

Command Syntax

CALL 'DB2SERV' 'D' STMT STMTL SQLCA RETCODE

The variables used in this command are described in the following table:

Variable Format/Length Explanation

STMT Annn Contains a command string which consists of SQL syntax as described above.

STMTL I2 Contains the length of the string defined in STMT.

SQLCA A136 Returns the current contents of the SQL communication area.

RETCODE

Returns an interface return code. The following codes are possible:

0	No warning or error occurred.
4	SQL statement produced an SQL warning.
8	SQL statement produced an SQL error.
12	Internal error occurred; the corresponding Natural error message number can be displayed with `SQLERR`.

The current contents of the SQLCA and an interface return code (RETCODE) are returned. The SQLCA is a collection of variables that are used by Db2 to provide an application program with information on the execution of its SQL statements.

The following two examples show you how to use DB2SERV with Function D.

Example of Function D - DEM2CREA:

  **************************************************************************
  *  DEM2CREA - CREATE TABLE NAT.DEMO                                      *
  **************************************************************************
  *
  DEFINE DATA
  LOCAL USING DEMSQLCA
  LOCAL
  *                                   Parameters for DB2SERV
  1 STMT         (A250)
  1 STMTL        (I2)     CONST <250>
  1 RETCODE      (I2)
  *
  END-DEFINE
  *
  COMPRESS  'CREATE TABLE NAT.DEMO'
    '(NAME        CHAR(20)     NOT NULL,'
    ' ADDRESS     VARCHAR(100) NOT NULL,'
    ' DATEOFBIRTH DATE         NOT NULL,'
    ' SALARY      DECIMAL(6,2),'
    ' REMARKS     VARCHAR(500))'
    INTO STMT
  CALL 'DB2SERV' 'D' STMT STMTL SQLCA RETCODE
  *
  END TRANSACTION
  *
  IF RETCODE = 0
    WRITE 'Table NAT.DEMO created'
  ELSE
    FETCH 'SQLERR'
  END-IF
  END
  **************************************************************************

Note:
The functionality of the DB2SERV Function D is also provided with the PROCESS SQL statement.

Example of Function D - DEM2SET:

  **************************************************************************
  *  DEM2SET - Set Current SQLID                                           *
  **************************************************************************
  *
  DEFINE DATA
  LOCAL USING DEMSQLCA
  LOCAL
  *                                   Parameter for DB2SERV
  1 STMT         (A250)
  1 STMTL        (I2)     CONST <250>
  1 RETCODE      (I2)
  1 OLDSQLID     (A8)
  1 NEWSQLID     (A8)
  *
  END-DEFINE
  *
  SELECT DISTINCT CURRENT SQLID
    INTO OLDSQLID
    FROM SYSIBM.SYSTABLES
  ESCAPE BOTTOM
  END-SELECT
  *
  MOVE  'SET CURRENT SQLID="PROD"';
    TO   STMT
  CALL 'DB2SERV' 'D' STMT STMTL SQLCA RETCODE
  *
  IF RETCODE > 0
    FETCH 'SQLERR'
  ELSE
    SELECT DISTINCT CURRENT SQLID
      INTO NEWSQLID
      FROM SYSIBM.SYSTABLES
    ESCAPE BOTTOM
    END-SELECT
  *
    WRITE ' Old SQLID was :' OLDSQLID
    WRITE ' New SQLID is  :' NEWSQLID
  END-IF
  *
  END
  **************************************************************************

When using SET CURRENT SQLID, the creator name of a table can be substituted by the current SQLID. This enables you to access identical tables with the same table name but with different creator names. Thus, table names must not be qualified by a creator name if this is to be substituted by the SQLID.

In all supported TP-monitor environments, the SQLID can then be kept across terminal I/Os until either the end of the session or its resetting via DB2SERV.

Function P

Function P invokes an Assembler module named NDBPLAN, which is used to establish and/or terminate the Db2 connection under TSO and in batch mode. This allows a Natural application to perform plan switching under TSO and in batch mode.

The program DEM2PLAN is an example of the use of DB2SERV with Function P.

The name of the current Db2 subsystem (#SSM) and the name of the new application plan (#PLAN) must be specified. In addition, an interface return code (#RETCODE) and the Db2 reason code (#REASON) are returned.

Command Syntax

CALL 'DB2SERV' 'P' #SSM #PLAN #RETCODE #REASON

Variable Format/Length Explanation

#SSM A4 Contains the name of the current Db2 subsystem.

#PLAN A8 Contains the new plan name.

#RETCODE

Returns an interface return code. The following codes are possible:

0	No warning or error occurred.
12	The specified new application plan is not scheduled.
99	The current environment is not a Call Attachment Facility (CAF) environment.
`nnn`	Return code from the CAF interface (see also the relevant Db2 literature by IBM).

#REASON I4 Returns the reason code of the CAF interface (see also the relevant Db2 literature by IBM).

Example of Function P - DEM2PLAN:

  **************************************************************************
  *  DEM2PLAN - Switch application plan under TSO/Batch with CAF interface *
  **************************************************************************
  *
  DEFINE DATA
  LOCAL
  *                                   Parameter for DB2SERV
  01 #SSM         (A4))    CONST <'DB2'>
  01 #PLAN        (A8
  01 #RETCODE     (I2)
  01 #REASON      (I4)
  *
  END-DEFINE
  *
  INPUT 'PLEASE ENTER NEW PLAN NAME' #PLAN (AD='_'I)
  *
  END TRANSACTION
  *
  CALL 'DB2SERV' 'P' #SSM #PLAN #RETCODE #REASON
  *
  DECIDE FOR FIRST VALUE OF #RETCODE
  *
    VALUE  0
      IGNORE
    VALUE  99
      INPUT 12/23 'This is not a CAF environment !!'
    VALUE  8,12
      INPUT 12/18 'New plan not scheduled, reason code'
                   #REASON (AD=OI EM=H(4))
    NONE
      INPUT 12/15 'CAF interface error'
                   #RETCODE (AD=OI EM=Z(3))
                  'with reason code'
                   #REASON (AD=OI EM=H(4))
  *
  END-DECIDE
  *
  END
  **************************************************************************

Important:
Plan switching under TSO and in batch mode is possible with the CAF interface only; see also the section Plan Switching under TSO and in Batch Mode.