Create DDM File (CRTDDMF)

The Create Distributed Data Management File (CRTDDMF) command creates a distributed data management (DDM) file.

A DDM file is used as a reference file to access a file located on a remote (target) system in the distributed data management network. The DDM file on the local system contains the name of the remote file and information identifying the remote system. It also specifies the method used to access the records in the remote file.

Parameters

Keyword Description Choices Notes
FILE DDM file Qualified object name Required, Positional 1
Qualifier 1: DDM file Name
Qualifier 2: Library Name, *CURLIB
RMTFILE Remote file Element list Required, Positional 2
Element 1: File Single values: *NONSTD
Other values: Qualified object name
Qualifier 1: File Name
Qualifier 2: Library Name, *LIBL, *CURLIB
Element 2: Nonstandard file 'name' Character value
RMTLOCNAME Remote location Single values: *RDB
Other values: Element list		 Required, Positional 3
Element 1: Name or address Character value, *DEVD
Element 2: Type *SNA, *IP
RDB Relational database Name Optional
TEXT Text 'description' Character value, *BLANK Optional
DEV Device Element list Optional
Element 1: APPC device description Name, *LOC
LCLLOCNAME Local location Communications name, *LOC, *NETATR Optional
MODE Mode Communications name, *NETATR Optional
RMTNETID Remote network identifier Communications name, *LOC, *NETATR, *NONE Optional
PORT Port number 1-65535, *DRDA Optional
ACCMTH Access method Single values: *RMTFILE, *COMBINED
Other values: Element list		 Optional
Element 1: Remote file attribute *KEYED, *ARRIVAL
Element 2: Local access method *BOTH, *RANDOM, *SEQUENTIAL
SHARE Share open data path *NO, *YES Optional
PTCCNV Protected conversation *NO, *YES Optional
LVLCHK Record format level check *RMTFILE, *NO Optional
AUT Authority Name, *LIBCRTAUT, *ALL, *CHANGE, *EXCLUDE, *USE Optional
REPLACE Replace file *YES, *NO Optional

DDM file (FILE)

Specifies the DDM file to be created.

This is a required parameter.

Qualifier 1: DDM file

name
Specify the name of the DDM file to be created.

Qualifier 2: Library

*CURLIB
The current library for the job is used to locate the DDM file. If no current library is specified as the current library for the job, QGPL is used.
name
Specify the name of the library where the DDM file is located.

Remote file (RMTFILE)

Specifies the name of the remote file as it is coded on the target system. This file name must be specified in code page 500. The remote file does not need to exist when the Distributed Data Management (DDM) file is created.

This is a required parameter.

Element 1: File

Single values

*NONSTD
The remote file name is not at standard IBM i file name. Specify the complete file name in apostrophes for the second element of this parameter.

Qualifier 1: File

name
Specify the name of the remote file as it is known on the remote system. If the remote system is an IBM i, specify the file name. The file name can be up to 10 characters in length. If the remote system is a System/36, the file name is the same as its System/36 file label. The file name can be up to eight characters in length. If the remote system is a System/38, a simple (unqualified) file name can be specified. The file name can be up to 10 characters in length. Labels for all other remote systems (including qualified file names for System/38) must use *NONSTD followed by the remote file name in apostrophes.

Qualifier 2: Library

*LIBL
All libraries in the library list for the current thread are searched until the first match is found.
*CURLIB
The current library for the job is used to locate the file. If no library is specified as the current library for the job, QGPL is used.
name
Specifies the library where the file is located.

Note: The library name is used only if the target system is an IBM i. If *CURLIB is specified, the current library in the called job on the target system is searched to locate the file. If *LIBL is specified, the library list in the called job on the target system is searched to locate the file.

Element 2: Nonstandard file 'name'

character-value
For target systems that allow naming conventions other than those used by the IBM i and System/36, and when specifying a qualified System/38 file name and when specifying a member name of a remote IBM i or System/38 file, specify up to 255 characters for the name of the remote file to be accessed. The name must be coded in the form required by the target system. The name must always be enclosed in apostrophes, and may contain lowercase letters, blanks, periods, or any other special characters.

Names for the IBM i, System/38, and System/36 must be in uppercase, and no blanks are allowed.

If the target system is an IBM i or a System/38, a file name, library name, and member name can all be specified. If a member name is specified, the full file name must be enclosed in apostrophes and must follow the value *NONSTD, and the member name must be enclosed in parentheses and immediately follow (with no space) either the library name (System/38) or the file name (IBM i).

Remote location (RMTLOCNAME)

Specifies the remote (target) system location name or address used with the distributed data management (DDM) file. The remote location name or address does not have to be defined before the DDM file is created, but it must be defined before the DDM file is opened. Multiple DDM files can use the same remote location for the target system.

This is a required parameter.

Single values

*RDB
The remote location information from the relational database entry specified for the Relational database (RDB) parameter is used to determine the remote system.

Element 1: Name or address

*DEVD
The remote location name defined in the device description specified for the Device (DEV) parameter is used.

Note: If *LOC is specified for the DEV parameter, a remote location name must be specified for this parameter.

character-value
Specify the name or address of the remote location that is associated with the target system. The remote location, which is used in accessing the target system, does not need to exist when the DDM file is created but must exist when the DDM file is opened. The remote location can take several forms:
  • SNA remote location name (LU name). Specify a maximum of 8 characters for the remote location name. If this form is used, the address type of this parameter must be *SNA (the default).
  • SNA remote network identifier and remote location name separated by a period. Specify a maximum of 8 characters for the remote location name, and a maximum of 8 characters for the remote network identifier. If this form of the parameter is used, the address type of this parameter must be *SNA (the default), and any value specified for the RMTNETID parameter must agree. If the RMTNETID parameter is not specified, the RMTNETID value will be set to agree with the RMTLOCNAME parameter.
  • IP address in dotted decimal form. Specify an internet protocol version 4 address in the form nnn.nnn.nnn.nnn where each nnn is a number in the range 0 through 255. If this form is used, the address type of this parameter must be specified as *IP.
  • IP address in colon hexadecimal form. Specify an internet protocol version 6 address in the form xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx where each xxxx is a hex number in the range 0 through FFFF. If this form is used, the address type of this parameter must be specified as *IP. IP version 6 includes the IPv4-mapped IPv6 address form (for example, : FFFF:1.2.3.4). For IP version 6, the compressed form of the address is allowed.
  • IP host domain name. Specify an internet host domain name of up to 254 characters in length. If this form is used, the address type of this parameter must be specified as *IP.

If *IP is specified for the address type, the DDM server at the remote location must support the use of TCP/IP, and the DEV, LCLLOCNAME, RMTNETID, and MODE parameters will be ignored.

If *IP is not specified, the DDM server must support SNA connectivity, and the PORT parameter will be ignored.

Element 2: Type

*SNA
The remote location has a Systems Network Architecture (SNA) address type.
*IP
The remote location has an Internet Protocol (IP) address type.

More information on remote locations is in the APPC Programming book, SC41-5443.

Relational database (RDB)

Specifies the relational database entry that is used to determine the remote location information for the DDM file.

name
Specify the name of the relational database entry that identifies the target system or target auxiliary storage pool (ASP) group. The relational database name can refer to a remote system or an ASP group that is configured and available on a remote system. The relational database entry does not need to exist when the DDM file is created but must exist when the DDM file is opened. This parameter is required when *RDB is specified for the Remote location (RMTLOCNAME) parameter.

Text 'description' (TEXT)

Specifies the text that briefly describes the object.

*BLANK
No text is specified.
character-value
Specify no more than 50 characters of text, enclosed in apostrophes.

Device (DEV)

Specifies the name of the source system communications device that is used with this distributed data management (DDM) file.

This parameter will be ignored if *IP is specified for the Remote location (RMTLOCNAME) parameter.

*LOC
The communications device associated with the remote location is used. If several devices can be associated with the remote location, the system determines which device is used.
name
Specify the name of a communications device that is associated with the remote location. If the device name is not valid for the remote location, an escape message is sent when the DDM file is opened.

Local location (LCLLOCNAME)

Specifies the local location name.

This parameter will be ignored if *IP is specified for the Remote location (RMTLOCNAME) parameter.

*LOC
The local location name specified for the remote location is used.
*NETATR
The LCLLOCNAME value specified in the system network attributes is used.
communications-name
Specifies the name of the local location used with the remote location name. The local location name is only specified to indicate a specific local location for the remote location.

More information on local location names is in the APPC Programming book, SC41-5443.

Mode (MODE)

Specifies the mode name that is used with the remote location name to communicate with the remote (target) system.

This parameter will be ignored if *IP is specified for the Remote location (RMTLOCNAME) parameter.

*NETATR
The mode in the network attributes is used.
BLANK
A mode name consisting of 8 blank characters is used.
communications-name
Specify the name of the mode.

More information on mode names is in the APPC Programming book, SC41-5443.

Remote network identifier (RMTNETID)

Specifies the identifier (ID) of the remote network in which the remote location resides. That ID is used to communicate with the remote (target) system.

If this parameter is specified, the Remote location (RMTLOCNAME) parameter must be consistent with this RMTNETID parameter. If the RMTLOCNAME parameter specified a network ID, this parameter must agree (otherwise, an error message will be issued). If the RMTLOCNAME parameter does not specify any network ID, there is no possibility of conflict with this parameter.

This parameter will be ignored if *IP is specified for the RMTLOCNAME parameter.

*LOC
The remote network ID specified for the remote location is used.
*NETATR
The remote network identifier specified in the network attributes is used.
*NONE
No remote network ID is used.
communications-name
Specify the remote network ID that is used with the remote location name. The remote network ID is specified only to indicate a specific remote network ID for the remote location.

More information on remote network IDs is in the APPC Programming book, SC41-5443.

Port number (PORT)

Specifies the TCP/IP port that is used at the remote location to communicate with the system on which the remote file is located.

This parameter will be ignored if *SNA is specified for the Remote location (RMTLOCNAME) parameter.

*DRDA
The DRDA well-known port of 446 will be used. This is the port on which the IBM i DDM TCP/IP server listens.
1-65535
Specify the port number to be used.

Access method (ACCMTH)

Specifies the DDM access method used to open the remote file and access its records. This parameter is ignored if the remote (target) system is a System/38 or an IBM i.

*RMTFILE
The source system selects the access method that is compatible with both the specified remote file and the access methods supported for that file by the remote (target) system. For systems other than the IBM i and System/38 target systems, if this value is used and the source system cannot select an access method when the file is opened, a message is sent to the program user. A different value must then be specified for this parameter, using the CHGDDMF command, after someone at the target system has been contacted about the appropriate access method information for the file.
*COMBINED
The DDM combined access method is used for the remote file. This access method combines the file processing capabilities of both the combined by key (*KEYED *BOTH) and the combined by record number (*ARRIVAL *BOTH) access methods. The record can be selected with a key value or a record number. The position can then be set relatively or randomly by key value or by record number. If duplicate keys are present in the file, they are processed in the order defined by each target system's implementation of the DDM architecture.

Element 1: Remote file attribute

*KEYED
Remote file is a keyed file.
*ARRIVAL
Remote file is a non-keyed file.

Element 2: Local access method

*BOTH
Remote file allows both sequential and random record access.
*RANDOM
Remote file allows random record access.
*SEQUENTIAL
Remote file allows sequential record access.

Determining the Access Method

The two elements of this parameter indicate the access method to be used to access the remote file. The following table shows the combinations of values for the ACCMTH parameter. The remote file attributes (in the far left column) refer to the type of file on the target system. The local access method (in the last three columns) refers to the way in which the source IBM i program intends to access the records in the remote file.

Figure: Access Method Combinations of Values
Relative by record number access method (*ARRIVAL *SEQUENTIAL):
This method allows access to records relative to the current position in record number sequence. The record number is not specified to identify the record.
Random by record number access method (*ARRIVAL *RANDOM):
This method allows access to records by specifying a record number in a random sequence determined by the requester.
Combined by record number access method (*ARRIVAL *BOTH):
This method combines the capabilities of the relative by record number and random by record number access methods.
Relative by key access method (*KEYED *SEQUENTIAL):
This method allows records in a keyed file accessed in key value sequence. Records can be accessed by moving forward or backwards in key sequence from the current record. The key value is not specified to identify the record.
Random by key access method (*KEYED *RANDOM):
This method allows records in a keyed file accessed in a random sequence. Records are selected by their key value and not their position in the file.
Combined by key access method (*KEYED *BOTH):
This method combines the capabilities of the relative by key and random by key access methods.

Share open data path (SHARE)

Specifies whether the open data path (ODP) is shared with other programs in the same routing step. When an ODP is shared, the programs accessing the file share facilities such as the file status and the buffer.

*NO
The ODP is not shared with other programs in the routing step. A new ODP for the file is created and used every time a program opens the file.
*YES
The same ODP is shared with each program in the job that also specifies *YES when it opens the file.

Protected conversation (PTCCNV)

Specifies whether the DDM conversation that is started for the DDM file is a protected conversation or not. A protected conversation is a conversation that uses two-phase commit protocols to ensure, even if a failure occurs, updates made on the remote system are synchronized with updates to other remote or local resources. A protected conversation is required to use two-phase commitment control with DDM. Two-phase commit is not implemented over TCP/IP for non-RDB DDM files, so protected conversations are not supported when the remote location type is *IP. Two-phase commit is implemented over TCP/IP for RDB DDM files. If a protected conversation is required when the remote location type is *IP, specify PTCCNV(*YES) with a *RDB remote location name for the RMTLOCNAME parameter and a relational database for the RDB parameter. More information on using two-phase commitment control with DDM is in the Distributed database programming topic collection in the IBM i Information Center at http://www.ibm.com/systems/i/infocenter/. PTCCNV(*NO) must be specified if *IP is specified for the Remote location (RMTLOCNAME) parameter.

*NO
The DDM conversation started, using this DDM file, is not a protected conversation.
*YES
The DDM conversation started, using this DDM file, is a protected conversation. Two-phase commitment control can be used with this DDM file.

Record format level check (LVLCHK)

Specifies whether the level identifiers of the record formats in the remote file are checked when the DDM file is opened by a program. If so, the record format identifiers in the program must match those in the remote file. If they do not match, an error message is sent to the requesting program and neither the DDM file nor the associated remote file is opened. Files that have an error while being opened are automatically closed. This parameter can be overridden by an Override with Database File (OVRDBF) command before the remote file is opened.

*RMTFILE
The level identifiers of the record formats of the remote file (identified in the RMTFILE parameter) are checked at the time the DDM file is opened.

If the target system is not a IBM i and not a System/38, the source IBM i creates a level check value based on the record length of the remote file and any key fields used in it. The created values are then compared to the values in the program, and they must match before the remote file can be opened. This reduces the chances of the wrong file being selected.

Note: Before this can be done for a system other than an IBM i or a System/38, the program must be compiled (or recompiled) using the DDM file. During the compilation, the DDM file is used to establish communications with the target system, get the remote file's attributes from the target system, and generate the level identifier values so they can be included in the compiled program for later level checking.

*NO
The level identifiers are not checked when the file is opened.

Authority (AUT)

Specifies the authority you are giving to users who do not have specific authority for the object, who are not on an authorization list, and whose group profile or supplemental group profiles do not have specific authority for the object.

Note: On the target system, the authority needed to access the remote file is also checked by using the user profile of the started job on the target system.

*LIBCRTAUT
The system determines the authority for the object by using the value specified for the Create authority (CRTAUT) parameter on the Create Library command (CRTLIB) for the library containing the object to be created. If the value specified for the CRTAUT parameter is changed, the new value will not affect any existing objects.
*CHANGE
The user can perform all operations on the object except those limited to the owner or controlled by object existence (*OBJEXIST) and object management (*OBJMGT) authorities. The user can change and perform basic functions on the object. *CHANGE authority provides object operational (*OBJOPR) authority and all data authority. If the object is an authorization list, the user cannot add, change, or remove users.
*ALL
The user can perform all operations except those limited to the owner or controlled by authorization list management (*AUTLMGT) authority. The user can control the object's existence, specify the security for the object, change the object, and perform basic functions on the object. The user also can change ownership of the object.
*USE
The user can perform basic operations on the object, such as running a program or reading a file. The user cannot change the object. Use (*USE) authority provides object operational (*OBJOPR), read (*READ), and execute (*EXECUTE) authorities.
*EXCLUDE
The user cannot access the object.
name
Specify the name of an authorization list. Users included on the authorization list are granted authority to the object as specified by the list. The authorization list must exist when the object is created.

Replace file (REPLACE)

Specifies whether an existing file, other than a save or database file, is replaced.

*YES
An existing file is replaced if the creation of a new DDM file with the same name and library is successful.
*NO
The creation of a new DDM file is not allowed if there is an existing file with the same name and library.

Examples

The following examples describe the creation of a DDM file.

Example 1: Creating a DDM File to Access a File on another IBM i 

CRTDDMF   FILE(SOURCE/SALES)  RMTFILE(REMOTE/SALES)
          RMTLOCNAME(NEWYORK)

This command creates a DDM file named SALES, and stores it in the SOURCE library on the source system. This DDM file uses the remote location named NEWYORK to access a remote file named SALES stored in the REMOTE library on an IBM i in New York.

Example 2: Creating a DDM File to Access a File Member on another IBM i 

CRTDDMF   FILE(SOURCE/SALES)  RMTLOCNAME(NEWYORK)
          RMTFILE(*NONSTD 'REMOTE/SALES(APRIL)')

This command creates the same file as in the previous example, except that now it accesses a specific member in the remote SALES file; the member is named APRIL.

Example 3: Creating a DDM File to Access a File on a System/38 

CRTDDMF   FILE(OTHER/SALES)  RMTLOCNAME(CHICAGO)
          RMTFILE(*NONSTD 'PAYROLL.REMOTE')

This command creates a DDM file named SALES, and stores it in the library OTHER on the source system. The remote location CHICAGO is used by the DDM file to access a remote file named PAYROLL in library REMOTE on a System/38.

Example 4: Creating a DDM File to Access a File on a System/36 

CRTDDMF   FILE(OTHER/SALES)  RMTFILE(PAYROLL)
          RMTLOCNAME(DENVER)  LVLCHK(*NO)

This command creates a DDM file named SALES, and stores it in the library OTHER on the source system. The remote location DENVER is used by the DDM file to access a remote file named PAYROLL on a System/36 in Denver. No level checking is performed between the PAYROLL file and the application programs that access it. Because the ACCMTH parameter was not specified, the access method for the target system is selected by the source system when the DDM file is opened to access the remote file.

Example 5: Creating a DDM File to Access a File through TCP/IP 

CRTDDMF   FILE(OTHER/SALES)  RMTFILE(PAYROLL)
          RMTLOCNAME(ROCHESTER.XYZ.COM *IP) PORT(*DRDA)

This command creates a DDM file named SALES, and stores it in the library OTHER on the source system. The remote location ROCHESTER.XYZ.COM is used by the DDM file to access a remote file named PAYROLL on a TCP/IP host with the domain name of ROCHESTER.XYZ.COM. The host listens on the standard DRDA port of 446. (Since *DRDA is the default port, the PORT parameter is not actually neccessary in this case.)

Example 6: Creating a DDM File to Access a File through TCP/IP using a dotted decimal IP version 4 address and a numeric port number 

CRTDDMF   FILE(OTHER/SALES)  RMTFILE(PAYROLL)
          RMTLOCNAME('9.5.36.17' *IP)  PORT(5021)

This command creates a DDM file named SALES, and stores it in the library OTHER on the source system. The remote location 9.5.36.17 is used by the DDM file to access a remote file named PAYROLL on a TCP/IP host with an IP address of 9.5.36.17. The host listens on port 5021.

Example 7: Creating a DDM File to Access a File through TCP/IP using a colon hexadecimal IP version 6 address and a numeric port number 

CRTDDMF   FILE(OTHER/SALES)  RMTFILE(PAYROLL)
          RMTLOCNAME('2001:DB8:0:B33D:8785:0:1734:F51C'
          *IP) PORT(32)

This command creates a DDM file named SALES, and stores it in the library OTHER on the source system. The remote location 2001:DB8:0:B33D:8785:0:1734:F51C is used by the DDM file to access a remote file named PAYROLL on a TCP/IP host with an IP address of 2001:DB8:0:B33D:8785:0:1734:F51C. The host listens on port 32.

Error messages

*ESCAPE Messages

CPF7302
File &1 not created in library &2.