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Several Natural subprograms and a non-Natural program (DB2SERV Interface, written in Assembler) are available to provide you with internal information from the Natural interface to SQL/DS or specific functions that are not available within the interface itself.

• Natural Interface Subprograms

• NDBDBRM Subprogram

• NDBDBR2 Subprogram

• NDBDBR3 Subprogram

• NDBERR Subprogram

• NDBISQL Subprogram

• NDBNOERR Subprogram

• NDBNROW Subprogram

• NDBSTMP Subprogram

• DB2SERV Interface

Natural Interface Subprograms

From within a Natural program, Natural subprograms are invoked with the CALLNAT statement and non-Natural subprograms are invoked with the CALL statement.

All Natural subprograms are provided in the library SYSSQL and should be copied to the SYSTEM or steplib library, or to any library where they are needed. The corresponding parameters must be defined by using either the DEFINE DATA statement in structured mode or the RESET statement in reporting mode.

The Natural subprograms NDBBRM, NDBDBR2, 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 current system file FNAT or the system file FUSER is used to locate the program to be examined depending on whether the library name begins with SYS or the library name does not begin with SYS.

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

Overview of Interface Subprograms

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 member provided with the subprogram (subprogram-nameT).

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 package name from the header of a Natural program generated as static (see also Preparing Natural Programs for Static Execution).

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

The #RESP parameter can contain the following response codes:

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 name from the header of a Natural program generated as static (see also Preparing Natural Programs for Static Execution) and the time stamp generated by the precompiler.

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

The #RESP parameter can contain the following response codes:

NDBDBR3 Subprogram

The Natural subprogram NDBDBR3 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, #DBRM '*DYNAMIC') and whether it has been modified for static execution (#RESP 0, #DBRM dbrmname). It is also used to obtain the corresponding DBRM 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 tape; it demonstrates how to invoke NDBDBR3. A description of the call format and of the parameters is provided in the text member 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:

The #RESP parameter can contain the following response codes:

NDBERR Subprogram

The Natural subprogram NDBERR replaces the E function 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 SQL code (which means a NAT3700 error); see Error Handling.

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

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 Adabas SQL Server documentation) can be passed to NDBISQL.

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

Valid functions for the #FUNCTION parameter are:

The #RESPONSE parameter can contain the following response codes:

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.

Notes:

1. Function code EXECUTE implicitly closes a cursor which has been opened by a previous EXECUTE call for a SELECT statement.
2. 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 SQL code. After the SQL call has been performed, NDBERR is used to investigate the SQL code; see Error Handling.

A sample program called CALLNOER is provided on the installation tape; it demonstrates how to invoke NDBNOERR. A description of the call format and of the parameters is provided in the text member 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 tape; it demonstrates how to invoke NDBNROW. A description of the call format and of the parameters is provided in the text member 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 SQL/DS, Natural provides a TIMESTAMP column as an alphanumeric field (A26) of the format YYYY-MM-DD-HH.MM.SS.MMMMMM; see also List Columns of an SQL Table.

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 SQL/DS time stamps and vice versa and performs SQL/DS time stamp arithmetics.

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

The functions available are:

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, which performs the SQL statement EXECUTE IMMEDIATE;

• Function U, which calls the database connection services (z/VSE batch mode only).

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 documentation. Examples can be found below and in the demonstration programs DEM2* in library SYSSQL.

Note:
The conditions that apply to issuing Natural END TRANSACTION or BACKOUT TRANSACTION statements also apply when issuing Natural 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:

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 SQL/DS to provide an application program with information on the execution of its SQL statements.

The following example shows 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 (see also the section SQL Statements in the Natural Statements documentation).

Function U

Function U calls the database connection services when running in batch mode under z/VSE; see also Sample Batch Verification Job (z/VSE only).

The user ID and password for the connection to SQL/DS must be assigned to the Natural program variables USER-ID and PASSWORD, respectively. An interface return code (RETCODE) is returned.

Command Syntax

CALL 'DB2SERV' 'U' USER-ID PASSWORD RETCODE

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

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