You use the Exchange module to import and export data toand from LN.
The Exchange module is mainly used for:
- Repetitive data replication for multisite environment
- Repetitive data replication for linking LN software to other software applications
- Data conversions from one version of LN to another
- Data conversions from other software to LN software the Exchange module controls the data export from LN tables to ASCII files and vice versa. You can also use the Exchange module to perform a data export. The changes in the database during the export process read from the audit files and are written to ASCII files. These changes are replayed at the target database during the import process.
The Exchange module has facilities to:
- Convert data
- Conditionally insert update, and delete data
- Control and monitor the process using log files the Exchange module is asynchronous and batch-oriented. The data exchange is performed by a batch process, which can be started manually or run based on a schedule that uses LN's job mechanism.
The Exchange module is divided into two major areas:
- Export of data
- Import of data
The Export module is used to create a sequential ASCII files filled with datafrom the LN database.The ASCII file can have its ownformat, which can be different from LN tables. You can also create thecorresponding definition file. This filecan be used to load the data definitions during the import procedure.
The Import module is used to read the sequential files createdby the Export module or by any other data source. The data from these files isput into LN tables.
The principle of an exchange procedure.
You can define exchange schemes in theMaster Data. Each exchange scheme has a uniquecode.
The exchange scheme has two major entities:
- ASCII files (Data Dump)
- Batches for conversion
ASCII Files
ASCII files and ASCII file fields form the first major part ofan exchange scheme. Theycontain the records that will be exchanged. Every line in that file representsa record. A record can have a fixed field length or a length that is definedwith a field separator.
Conditions can be used tomanipulate the values of the ASCII files fields in the exchange process. Theycan be specified per exchange scheme. A conditionis maintained using LN 3GL/4GL statements in the text editor. Various functions and variables areprovided to simplify the condition text. After the condition is created, itssyntax must be checked.
Batches
Batches are the entities that contain relationships betweenASCII files and LN tables.
The relationships between the ASCII files and the LN tables are defined intable and field relationships. To import and export alike, you can specifythese relationships per batch line.
Import of Data
Batches consist of table and field relations. The table relations for importspecify which data of the ASCII file(s) will be transferred to which LN table. Aone-to-many relation between LN tables and ASCII files is possible. Each entry forms a line in abatch. Conditions can also be linked to a table relation.
Four condition types can be defined:
- Insert condition
- Overwrite condition
- Update condition
- Delete condition
The corresponding action is only carried out if the returnvalue of the conditions linked to the action is true.
For each relation table you can maintain relations at fieldlevel. These relations state which field in the ASCII file must fill a field inthe LN table. Acondition can also be linked at this level. The output of the condition is thevalue of the field.
Export of Data
In case of an export of data the table relations indicate whichdata from the LN tables must be transferred to which ASCII files. One ASCII file can import datafrom only one LN table, but exceptions can be made by using conditions. In that case, you canput data of related tables in the same ASCII file. Each entry forms a tablerelation for export. Relations on field level can be maintained per tablerelation. These relations define how each field in the ASCII file must befilled.
The standard bdbpre program can also be used to create ASCIIfiles, but this can only be done if the structure of the ASCII file is identical tothe data definition of the LN table, and the export is not based onaudit.
the Exchange (XCH) module process
After the exchange scheme is created and the import or export program is generated, the exchange process can be carried out by starting one of the following sessions:
- Import Data (Non-Regular) (daxch0223m000)
- Import Data (on a Regular Basis) (daxch0224m000)
- Export Data (Non-Regular) (daxch0233m000)
- Export Data (on a Regular Basis) (daxch0234m000)
Every exchange scheme code represents a different scheme. Forconversion of a standard package, for example an upgrade of LN, one exchangescheme can be provided. A new exchange scheme can be created to customize theexchange to specific needs. It is possible to copy the exchange scheme from onecode to another and to modify the other to suit the requirements. By providingthe concept of a parent exchange scheme, copying data can be restricted to onlythose parts that differ from the exchange scheme.
Related topics
- Introduction to the master data business object
- Introduction to the import module
- Introduction to the export module
- Introduction to multisite control
- Introduction to the miscellaneous business object
- Import using the Data Access Layer (DAL)
- Infor LN Exchange - User Guide (U8405)
