Locked symbols

In object management, the software manages the fact that a user is in the process of modifying a record by blocking a symbol. This locking, obtained by the L4G instruction Lock, corresponds to the creation of an entry identified by a character string (a symbol) in a table in the database: the APLLCK table, which manages the locked symbols.

This is NOT however line locking in the database sense. Indeed:

• a line lock in the database is managed by the internal mechanisms in the database. It is provoked by the Readlock instructions or by the With Lock clauses in other instructions, or by the fact that the lines in the database are being modified in a transaction. It lasts the time of a transaction, that is to say the least time possible to avoid inter-locking situations. it is excluded from interrupting a process by an entry likely to make this type of locking uncontrollable.
• this type of locking is a logical locking, which is used to avoid that another user can simultaneously lock the same symbol. This locking is assured in the software by the object management and to control the execution of certain functions that should be run in mutually exclusive fashion.

The easiest way to see that a record is locked in object management is the presence of an icon representing a key in the bar at the bottom of the screen. This key means that when you read the record, it was locked. An attempt to modify the record will check if the lock is still present. If it is no longer locked, the user who attempted the modification will in turn lock the record. If a key is missing when you read the record without any modification restriction, the lock is set.

In standard or combined object management, the symbol used in the object management is constructed from the object code followed by the current key. If there is more than one segment of a key, place the second component first (it is usually the most descriptive), followed by the backslash (\), followed by the key's first component (then as required, the remaining segments in order from the 3^rd, always using the same separator).

In table object management, when all of the table is locked, the name of the table is used as the symbol.

In this way, for example:

• if the MARTIN user record is modified, the symbol AUSMARTIN is locked.
• if the analytical dimension COMMERCE is modified on the 3 analytical axis, the symbol CCECOMMERCE\3 is locked
• if the language table is modified, the symbol TABLAN is locked.

The symbol verification function is used to display the list of symbols locked in this way.