Notation
Version numbers must be noted in the description file as concisely as possible (i.e. with no trailing '0's, except for whole version numbers). A '.' is used as the decimal separator.
Incorrect notation will result in a search error (the "Error during update sequence" message).
Example:
1.0 |
=> ok |
1.1 |
=> ok |
1 |
=> error (1.0) |
1.10 |
=> error (1.1) |
01.00 |
=> error (1.0) |
Re-entry and resumption after an error
We recommend working as follows, to ensure that an error cannot corrupt the database during an update sequence:
Use generic table creation scripts.
The scripts in the [PDM/Generic] section are reentrant. As such, they can be executed several times without altering the database.Let the tool manage transactions implicitly.
The scripts in the [Data/*] section are executed in transactions. If an error occurs, the whole script is cancelled, unless the transaction has been expressly validated at a set point (\commit); this lets the system restart with the database in a "stable state"."Close" the loops in the update sequence cleanly by inserting a version number at the end of the Data sequence.
This enables the utility to restart from the point nearest the error in the event of an incident (once any necessary corrective measures have been taken).With AS/400, work in logged mode with one or more SQL collections. Otherwise, the Data scripts will be run in AUTOCOMMIT mode, and will not be reentrant.
Note: if you are not working with a collection, the new tables created will not be logged by default, and an error will occur if you attempt to run the Data scripts in logged mode (via the logged option).