Service module to handle common interactions with the Linear Hash database.

Syntax

Response = Database_Services(@Service, @Params)

Returns

The meaning of the response value depends on the service.

Parameters

ParameterDescription
@ServiceThe name of the service being requested. Required.
@ParamsGeneric parameters. Refer to a specific service to determine the actual parameters used.

Remarks

This module provides several useful services for high level interaction with database tables and rows.

Services

ServiceDescription
VerifyLHAll

Usage:
Database_Services('VerifyLHAll')

Comments:
Performs a health check against all attached tables and returns back any issues.

Returns:
Returns two lists which are delimited by an @RM. The first list is an @FM list of attached tables. The second list is an @FM list of results (groups that have GFEs or an empty string if there are none). Items in each list correspond which each other based on their list position.

VerifyLH

Usage:
Database_Services('VerifyLH', Tablenames, SaveList)

Comments:
Performs a health check against the indicated tables and returns back any issues. Note: This uses the Verify_LH subroutine to check for GFEs. All results are stored in the SYSLHVERIFY table with a KeyID of VolumeLabel*DatabaseID*TableName. Returns the list of groups that have GFEs or returns an empty string if there are none. The list of GFEs or empty strings will themselves be @FM delimited to correspond with the tables passed into this service.

Returns:
An @FM delimited array of table names and associated GFE information.

GetTableProperties

Usage:
Database_Services('GetTableProperties', TableName)

Comments:
Returns an array of information related to the database table being passed in.

Returns:
An @FM delimited array of table information:

AttributeDescription
<1>Database ID
<2>MFS/BFS list
<3>Volume Label (if available)
<4>Volume Path (if available)
<5>BFS (if available)

GetTableHandle

Usage:
Database_Services('GetTableHandle', TableName)

Comments:
Returns an array of information related to the database table being passed in.

Returns:
The handle array created by the Open statement.

ClearTableHandle

Usage:
Database_Services('ClearTableHandle', TableName)

Comments:
Clears the table handle array array from cache. This will force the GetTableHandle service to call the Open statement again.

Returns:
N/A

ReadDataRow

Usage:
Database_Services('ReadDataRow', KeyID, NotExpired, ExpirationDuration, IgnoreMFSRoutines)

Comments:
Reads a data row for the indicated Key ID and database table.

Returns:
The requested data row.

WriteDataRow

Usage:
Database_Services('WriteDataRow', TableName, KeyID, DataRow, IgnoreSelfLock, IgnoreMFSRoutines, IgnoreAllLocks)

Comments:
Writes a data row for the indicated Key ID and database table.

Returns:
N/A

DeleteDataRow

Usage:
Database_Services('DeleteDataRow', TableName, KeyID, IgnoreSelfLock, IgnoreMFSRoutines)

Comments:
Deletes a data row for the indicated Key ID and database table.

Returns:
N/A

GetKeyIDLock

Usage:
Database_Services('GetKeyIDLock', TableName, KeyID, IgnoreSelfLock)

Comments:
Attempts to perform a semaphore lock on the indicated tablename and Key ID.

Returns:
A Boolean flag indicating if the lock request was successfully performed.

ReleaseKeyIDLock

Usage:
Database_Services('ReleaseKeyIDLock', TableName, KeyID)

Comments:
Attempts to release a semaphore lock on the indicated tablename and Key ID.

Returns:
A Boolean flag indicating if the lock release was successfully performed.

SetTableAlias

Usage:
Database_Services('SetTableAlias', TableName, AliasName, Volume, DatabaseID)

Comments:
Attempts to create an alias for the indicated table, volume, and database. It returns a True$ if successful or a False$ if unsuccessful.

Returns:
A Boolean flag indicating if the alias request was successfully performed.

SearchIndex

Usage:
Database_Services('SearchIndex', TableName, ColumnName, SearchValue, UpdateIndex)

Comments:
Returns an @FM delimited list of Key IDs that match the search value.

Returns:
See comments

CalculateColumn

Usage:
Database_Services('CalculateColumn')

Comments:
Called directly from within a calculation column. The name of the table and column is derived from the call stack and the associated table commuter, if it exists, is called with the appropriate arguments.

Returns:
The result of the calculated column.

GetTableCommuter

Usage:
Database_Services('GetTableCommuter', TableName)

Comments:
Returns the name of the indicated table's commuter module if it exists. If it does not exist then an empty string will be returned.

Returns:
See comments.

GetUserLocks

Usage:
Database_Services('GetUserLocks')

Comments:
Note, this can only be done with the UD 5. This can also cause instability with the current session and may require the Task Manager to close the session.

Returns:
Returns a dynamic array of user lock information.

IsKeyIDLocked

Usage:
Database_Services('IsKeyIDLocked', TableName, KeyID, IgnoreSelfLock)

Comments:
Returns a Boolean flag of the lock status for the indicated table and Key ID.

Returns:
See comments.

IsKeyIDSelfLocked

Usage:
Database_Services('IsKeyIDSelfLocked', TableName, KeyID)

Comments:
Returns a Boolean flag of the self-lock status for the indicated table and Key ID.

Returns:
See comments

UnlockKeyID

Usage:
Database_Services('UnlockKeyID', TableName, KeyID)

Comments:
Attempts to unlock the indicated Key ID from the indicated Table Name. Note, this can only be done with the UD 5.

Returns:
A Boolean flag indicating if the unlock request was successfully performed.

Params

The proper use of the generic arguments are defined in the definition of each service above.


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