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Doxport

Doxport is a library to mix Doctrine and a bit of graph theory to get stuff done. Specifically, it aims to give you powerful exporting and archiving tools for a relational Doctrine2 schema.

Doxport uses Doctrine 2.4, Clue/Graph, and Symfony components. It's PHP 5.4+ and, at this stage, probably a bit MySQL-specific (although the guts should be solid).

Given a relational schema, usually via class annotations, Doxport should let you safely archive, delete or import partial data from related tables, in the correct order.

Installation

Doxport is installed via Composer. The package name is vend/doxport.

Actions

Delete

The delete action removes rows from the database, and saves their content to the output directory. If the eio extension is loaded, these files will be sync'd at the point the entity manager is flushed and the rows actually removed.

Export

Like the delete action, the export action saves row content to the output directory. However, it does not remove rows from the database. This means you won't be able to immediate import a set of exported data into the same database, because you'll get primary key errors. However, you can import into a fresh database, and this action is very useful for taking backups without disturbing the original data.

Import

The import action takes a path to a previously output set for data (usually from the export or delete actions). By reading the dumped constraint information, Doxport figures out the correct order to import the data, and does so.

Algorithm

Doxport uses a bit of graph theory, so you might want to read up on these before jumping in:

• Directed acyclic graphs: DAGs for short
• Topological sorting: basically, produces a dependency-safe order to walk the nodes of a DAG

Outline

To start with, you tell Doxport the root entity type, and give it some criteria to apply to this type. For example, you might say the root entity is My\Namespace\User, and the criteria is id == <some value>.

Then, Doxport will:

1. Create a DAG with all tables in the database as the nodes, and all associations between them as the edges
2. Filter the edges to only consider 'constraining associations'
   • Usually this means only associations that actually own the foreign key, and have a foreign key constraint
3. Filter the nodes to only consider tables still associated with the root entity after the edge filtering
   • This step removes irrelevant tables. For example, only tables associated with the user type (via any number of relations)
4. Produce a topological sort of this DAG
5. For each node, in the order of the topological sort, find the shortest path back to the root entity, using a slightly different filtered DAG
   • The filtering is slightly different for this DAG because we additionally only consider edges that are 'covered' by an index

Each time step 5 occurs, an action is invoked on the resulting query. This might be export or delete, for example.

Configuration

Doxport follows a similar configuration approach to Doctrine2 (when installed as a composer project; Symfony2 does this set up for you). You're expected to create a file named cli-config.php or config/cli-config.php. This PHP file should return a HelperSet, which can be produced from an EntityManager via Doctrine2's ConsoleRunner:

See Doctrine2's configuration and installation guide, and particularly the chapter on CLI tool setup, for more information.

Once you've done that, Doxport runs as a Composer bin script:

Excluding Associations

Sometimes, you may want to exclude a relation or entity type from being considered for Doxport operations. You can do this using annotations. All these annotations are in the Doxport\Annotation namespace.

To use these annotations, you'll first need to register the annotation namespace with the registry. You can do that like this:

The path to use is the relative path to the root Doxport namespace. If you don't know where this is, you can use a Composer autoloader instance to help find it.

Output

Directory

By default, the output directory is is build/<action>/<criteria>_<value>. You can change the location of the output with the --data-dir option.

Files

Within the output directory, you'll find a file for each entity type. There are also a few additional files:

• constraints.png: A graphviz image of the constraint graph, useful for debugging the produced DAG
• constraints.txt: The topological order the entities were dumped in (one entity type per line). Used (in reverse) to decide the order to import.

Format

By default, Doxport will output to JSON format. This can be changing using the --format option. The JSON format is an array of objects.