| Where allowed to run: All environments (*ALL) Threadsafe: No |
Parameters Examples Error messages |
The Change Distributed Data Management File (CHGDDMF) command changes, in the distributed data management file (DDM) description, one or more of the attributes of the specified DDM file. The DDM file is used as a reference file by programs on the System i5 to access files located on any target system in the System i5 DDM network.
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| Keyword | Description | Choices | Notes |
|---|---|---|---|
| FILE | DDM file | Qualified object name | Required, Key, Positional 1 |
| Qualifier 1: DDM file | Name | ||
| Qualifier 2: Library | Name, *LIBL, *CURLIB | ||
| RMTFILE | Remote file | Single values: *SAME Other values: Element list |
Optional, 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 |
Optional, Positional 3 |
| Element 1: Name or address | Character value, *SAME, *DEVD | ||
| Element 2: Type | *SAME, *SNA, *IP | ||
| LVLCHK | Record format level check | *SAME, *RMTFILE, *NO | Optional |
| RDB | Relational database | Name, *SAME | Optional |
| TEXT | Text 'description' | Character value, *SAME, *BLANK | Optional |
| DEV | Device | Element list | Optional |
| Element 1: APPC device description | Name, *SAME, *LOC | ||
| LCLLOCNAME | Local location | Communications name, *SAME, *LOC, *NETATR | Optional |
| MODE | Mode | Communications name, *SAME, *NETATR | Optional |
| RMTNETID | Remote network identifier | Communications name, *SAME, *LOC, *NETATR, *NONE | Optional |
| PORT | Port number | 1-65535, *SAME, *DRDA | Optional |
| ACCMTH | Access method | Single values: *SAME, *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 | *SAME, *NO, *YES | Optional |
| PTCCNV | Protected conversation | *SAME, *NO, *YES | Optional |
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Specifies the distributed data management (DDM) file to be changed.
This is a required parameter.
Qualifier 1: DDM file
Qualifier 2: Library
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Specifies the name of the remote file as it is coded on the target system. The remote file does not need to exist when the Distributed Data Management (DDM) file is changed.
Note: This file name must be specified in code page 500.
Single values
Element 1: File
Single values
Qualifier 1: File
Qualifier 2: Library
Note: The library name is used only if the target system is a System i5.
Element 2: Nonstandard file 'name'
Names for the System i5, System/38, and System/36 must be in uppercase, and no blanks are allowed.
If the target system is a System i5 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 (System i5).
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Specifies the remote (target) system location name or address used with the distributed data management (DDM) file. Multiple DDM files can use the same remote location for the target system.
Single values
Element 1: Name or address
Note: If *LOC is specified for the DEV parameter, a remote location name must be specified for this parameter.
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
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Specifies whether the level identifiers in the program are checked with the level identifiers of the record formats in the remote file when the distributed data management (DDM) file is opened. If they do not match, an error message is sent to the program requesting the open, and neither the DDM file nor the associated remote file is opened. This parameter value can be overridden by an Override Database File (OVRDBF) command before the remote file is opened.
Note: For systems other than System i5, the program must be compiled (or recompiled) by using the DDM file. During the compile operation, the DDM file is used to establish communications with the target system, get the remote file's attributes from the target system, and create the level identifier values so they can be included in the compiled program for later level checking.
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Specifies the relational database entry that is used to determine the remote location information for the DDM file.
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Specifies the text that briefly describes the object.
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Specifies the name of the advanced program-to-program communications (APPC) device description on the source system that is used with this DDM file.
This parameter will be ignored if *IP is specified for the Remote location (RMTLOCNAME) parameter.
More information on device names is in the APPC Programming book, SC41-5443.
Note: If *DEVD is specified for the RMTLOCNAME parameter for the remote location, a device name must be specified for this parameter.
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Specifies the local location name.
This parameter will be ignored if *IP is specified for the Remote location (RMTLOCNAME) parameter.
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Specifies the mode name that is used with the remote location name to communicate with the target system.
This parameter will be ignored if *IP is specified for the Remote location (RMTLOCNAME) parameter.
More information on mode names is in the APPC Programming book, SC41-5443.
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Specifies the remote network identifier (remote network ID) in which the remote location resides, and which is used to communicate with the target system.
If this parameter is specified, the value specified for the Remote location (RMTLOCNAME) parameter must be consistent with the 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.
More information on remote network IDs is in the APPC Programming book, SC41-5443.
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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.
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Specifies the distributed data management (DDM) access method used to open the remote file and access its records when the target system is not a System i5. Specifying a value other than *RMTFILE for this parameter may improve performance when requests to remote files are processed on the target system. This parameter is ignored when the target system is a System i5 system or a System/38. The remote system file is accessed as if it is a local file.
Single values
Element 1: Remote file attribute
Element 2: Local access method
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 System i5 program intends to access the records in the remote file.
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Remote Local Access Method
File
Attributes *SEQUENTIAL *RANDOM *BOTH
---------- ------------ ------------ ------------
*ARRIVAL Relative by Random by Combined by
record number record number record number
*KEYED Relative by Random by Combined by
key key key
|
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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.
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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. 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.
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The following examples describe the changing of a DDM file.
Example 1: Changing the Communications Mode System
CHGDDMF FILE(SOURCE/SALES) MODE(MODEX)
This command changes the communications mode for the DDM file named SALES stored in the SOURCE library on the source system. The mode is changed to MODEX.
Example 2: Changing a DDM File to Access a File through TCP/IP
CHGDDMF FILE(OTHER/SALES) RMTLOCNAME(ROCHESTER.XYZ.COM *IP)
PORT(*DRDA)
This command changes the remote location name for the DDM file named SALES stored in the OTHER library on the source system. The remote location is changed to the TCP/IP host having the domain name of ROCHESTER.XYZ.COM. The host listens on the standard DRDA port of 446.
Example 3: Changing a DDM File to Access a File through TCP/IP using a dotted decimal IP version 4 address and a numeric port number
CHGDDMF FILE(OTHER/SALES) RMTLOCNAME('9.5.36.17' *IP)
PORT(5021)
This command changes the remote location name for the DDM file named SALES stored in the OTHER library on the source system. The remote location is changed to the TCP/IP host with the IP address of 9.5.36.17. The host listens on port 5021.
Example 4: Changing a DDM File to Access a File through TCP/IP using a colon hexadecimal IP version 6 address and a numeric port number
CHGDDMF FILE(OTHER/SALES)
RMTLOCNAME('2001:DB8:0:B33D:8785:0:1734:F51C'
*IP) PORT(32)
This command changes the remote location name for the DDM file named SALES stored in the OTHER library on the source system. The remote location is changed to the TCP/IP host with the IP address of 2001:DB8:0:B33D:8785:0:1734:F51C. The host listens on port 32.
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