Dave Rolsky

NAME

Alzabo::MySQL - Alzabo and MySQL

DESCRIPTION

This documentation is about what special support Alzabo has for MySQL, as well as what is lacking.

MySQL support is based on the 3.23.* release series, with some support for features that are starting to appear in the 4.0.* releases. Earlier versions of MySQL will probably work with Alzabo, though Alzabo cannot magically make these releases support new features like fulltext indexes.

Indexes

  • Alzabo supports the ability to specify prefixes when adding an index. Prefixes are required when attempting to index any sort of text or blob column.

  • Alzabo supports the creation of fulltext indexes and their use in SELECT and WHERE clauses. This includes the ability to get back the score given for a match as part of a select, using the function or select methods of either table or schema objects.

Reverse Engineering

  • When reverse engineering a schema, Alzabo knows that MySQL has "default defaults" for certain column types. For example, if a DATE column is specified as NOT NULL but is not assigned a default, MySQL gives this column a default of '0000-00-00'.

    Because Alzabo knows about this, it will ignore these defaults when reverse engineering an RDBMS.

  • Similarly, Alzabo knows that MySQL assigns default "lengths" to many column types. For example, if given INTEGER as a column type, MySQL will convert this to INTEGER(11) or INTEGER(10), depending on the version of MySQL being used.

    Again, Alzabo ignores these lengths when reverse engineering a schema.

  • All of this may lead to apparent inconsistencies when using the with the Alzabo::Create::Schema->sync_backend or Alzabo::Create::Schema->sync_backend_sql methods. If you are using this feature from the web based schema creator, you will see that even immediately after running the sync_backend() method, Alzabo may still think there are differences between the two schemas. This is not a problem, as running the SQL Alzabo generates will not actually change your database.

Transactions

    Alzabo will try to use transactions whenever appropriate. Unfortunately, there is no way to determine whether or not a given table supports transactions so Alzabo simply calls DBI's begin_work() method, whether or not this will actually do anything.

Constraints and Foreign Keys

  • Column constraints are treated as column attributes.

  • Foreign key constraints are not generated when generating SQL for a MySQL schema. This will probably change in the future.

Table Types

    These can be specified as a table attribute.




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