DBAL-223: Add DBAL TableGenerator #1397

Closed
doctrinebot opened this Issue Feb 13, 2012 · 3 comments

2 participants

@doctrinebot

Jira issue originally created by user @beberlei:

/****
 * Table ID Generator for those poor languages that are missing sequences.
 *
 * WARNING: The Table Id Generator clones a second independent database
 * connection to work correctly. This means using the generator requests that
 * generate IDs will have two open database connections. This is necessary to
 * be safe from transaction failures in the main connection. Make sure to only
 * ever use one TableGenerator otherwise you end up with many connections.
 *
 * TableID Generator does not work with SQLite.
 *
 * The TableGenerator does not take care of creating the SQL Table itself. You
 * should look at the `TableGeneratorSchemaVisitor` to do this for you.
 * Otherwise the schema for a table looks like:
 *
 * CREATE sequences (
 *   sequence_name VARCHAR(255) NOT NULL,
 *   sequence_value INT NOT NULL DEFAULT '1',
 *   sequence*increment*by INT NOT NULL DEFAULT '1',
 *   PRIMARY KEY (table_name)
 * );
 *
 * Technically this generator works as follows:
 *
 * 1. Use a robust transaction serialization level.
 * 2. Open transaction
 * 3. Acquire a read lock on the table row (SELECT .. FOR UPDATE)
 * 4. Increment current value by one and write back to database
 * 5. Commit transaction
 *
 * If you are using a sequence*increment*by value that is larger than one the
 * ID Generator will keep incrementing values until it hits the incrementation
 * gap before issuing another query.
 *
 * If no row is present for a given sequence a new one will be created with the
 * default values 'value' = 1 and 'increment_by' = 1
 *
 * @author Benjamin Eberlei <kontakt@beberlei.de>
 */
@doctrinebot

Comment created by @beberlei:

Implemented under the DDC-450 label, will get into ORM through this implementation.

@doctrinebot

Issue was closed with resolution "Fixed"

@beberlei beberlei was assigned by doctrinebot Dec 6, 2015
@doctrinebot doctrinebot added this to the 2.3 milestone Dec 6, 2015
@doctrinebot doctrinebot closed this Dec 6, 2015
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment