Modifies the location of log files corresponding to an HFSQL data file (*JNL files as well as JournalOperation and JournalIdentification files if they exist).
Reminder: The JournalOperation and JournalIdentification files are created:
- if the management of replication is requested for the data file.
- if the management of the selected log corresponds to "Write-to-file log and history of accesses".
The *JNL file is not created if only the log of access history is requested.
By default, the physical files corresponding to the logs are created:
- in the directory specified in the analysis ("Analysis description", "Log process" tab).
- in the specified directory when describing the data file ("Description of data file" in the context menu, "Miscellaneous" tab). This option is available only if the analysis directory corresponds to "<Default directory of files>".
Remark: From version 19, HFSQL is the new name of HyperFileSQL.
// The "Customer" file has a log
HChangeLogDir(Customer, "\\MyServer\Log\JNL", "\\MyServer\Log\Operation")
...
HAdd(Customer)
// -> the "CustomerJNL" file is opened
// in the "\\MyServer\Log\JNL" directory
//-> the "JournalOperation" and "JournalIdentification" files
// are opened in the "\\MyServer\Log|Operation" directory
...
Syntax
<Result> = HChangeLogDir(<Data file> , <JNL file location> [, <LogOperation file location> [, <Backup location>]])
<Result>: Boolean
- True if the operation was performed,
- False if a problem occurs. HErrorInfo is used to identify the error.
<Data file>: Character string
Name of the data file whose log must be moved. This is the logical name of the file (defined in the data model editor).
If this parameter is equal to "*", all the data files found in the current analysis will have their log file moved.
<JNL file location>: Character string
New access path to JNL file associated with the file with logs (full or relative path).
If this parameter corresponds to an empty string (""), the current file location is not modified.
<LogOperation file location>: Optional character string
New access path to JournalOperation file and JournalIdentification file associated with the file with logs (full or relative path). The JournalOperation file contains all the operations performed on the file with logs.
If this parameter is not specified or if it corresponds to an empty string (""), the current file location is not modified.
<Backup location>: Optional character string
Path of backups of log files. By default, this path corresponds to: <directory of JNL files>\__JNLBackupThis path is used during the automatic modification of data files to archive the logs.
HHistoryModification will also search for change history in these files.
If this parameter corresponds to an empty string (""), the current location is not modified.
If this parameter corresponds to a relative path (and starts with a dot), the path will be relative to data files.
Remarks
Priority for defining the location of log files
The location of log files is defined according to the following priority order:
- Location specified when creating the logged file (HCreation).
- Location specified by HChangeLogDir.
- Location specified in the analysis.
- Location of logged file.
The log file exists when HChangeLogDir is used
If the log file already exists during the call to HChangeLogDir, this log file is not used anymore: a log file is created at the specified location and it is associated with the HFSQL file.
Using HDeclareExternal with a file with logs: if an application uses
HDeclareExternal on a file with a log, the changes made by this application are saved in the log files specified in the header of the HFSQL file.
Miscellaneous
- If the files are opened while the directory is modified, the files are automatically closed.
- If the path of the log is redefined several times by HChangeLogDir, only the last path is used. The modification is effective for all the applications that use the file with logs.
Replication and log process
Reminder: The replication is based on the logs and on the operation tables of the data files. The replication fails if the location of the logs and operation tables is invalid.