Symfony Doctrine Models for Entity Without Primary

I'm working with a legacy database while re-building the web application. I want to use Symfony2.x which obviously has Doctrine as ORM.

I've around 50 (mysql) tables which has NO Primary Keys. When I try to generate models, it does not let me do and throw an exception with "No Primary Key on ... table".

Do I must have Primary Keys on tables to use Doctrine or is there any way around it?

Any help would be great.

Thanks.

回答1:

Doctrine requires every entity class to have an identifier/primary key.

Take a look at this page: http://www.doctrine-project.org/docs/orm/2.0/en/reference/basic-mapping.html#identifiers-primary-keys

回答2:

It is a requirement for Doctrine to have an identifier/primary key. Take a look at this page: http://www.doctrine-project.org/docs/orm/2.0/en/reference/basic-mapping.html#identifiers-primary-keys

But there is a way to generate mappings and entities from tables that do not have a primary key. A table with no primary key is an unusual and bad database design but such a scenario exists in case of legacy databases.

Solution:
Note: All references below refer to Doctrine 2.0
1. Find the file DatabaseDriver.php (in Doctrine/ORM/Mapping/Driver/DatabaseDriver.php)
2. Find the method reverseEngineerMappingFromDatabase. Modify the code as stated below.
The original code is:

private function reverseEngineerMappingFromDatabase()
    {
        if ($this->tables !== null) {
            return;
        }

        $tables = array();

        foreach ($this->_sm->listTableNames() as $tableName) {
            $tables[$tableName] = $this->_sm->listTableDetails($tableName);
        }

        $this->tables = $this->manyToManyTables = $this->classToTableNames = array();
        foreach ($tables as $tableName => $table) {
            /* @var $table \Doctrine\DBAL\Schema\Table */
            if ($this->_sm->getDatabasePlatform()->supportsForeignKeyConstraints()) {
                $foreignKeys = $table->getForeignKeys();
            } else {
                $foreignKeys = array();
            }

            $allForeignKeyColumns = array();
            foreach ($foreignKeys as $foreignKey) {
                $allForeignKeyColumns = array_merge($allForeignKeyColumns, $foreignKey->getLocalColumns());
            }

            if ( ! $table->hasPrimaryKey()) {
                throw new MappingException(
                    "Table " . $table->getName() . " has no primary key. Doctrine does not ".
                    "support reverse engineering from tables that don't have a primary key."
                );
            }

            $pkColumns = $table->getPrimaryKey()->getColumns();
            sort($pkColumns);
            sort($allForeignKeyColumns);

            if ($pkColumns == $allForeignKeyColumns && count($foreignKeys) == 2) {
                $this->manyToManyTables[$tableName] = $table;
            } else {
                // lower-casing is necessary because of Oracle Uppercase Tablenames,
                // assumption is lower-case + underscore separated.
                $className = $this->getClassNameForTable($tableName);
                $this->tables[$tableName] = $table;
                $this->classToTableNames[$className] = $tableName;
            }
        }
    }

The modified code is:

private function reverseEngineerMappingFromDatabase()
    {
        if ($this->tables !== null) {
            return;
        }

        $tables = array();

        foreach ($this->_sm->listTableNames() as $tableName) {
            $tables[$tableName] = $this->_sm->listTableDetails($tableName);
        }

        $this->tables = $this->manyToManyTables = $this->classToTableNames = array();
        foreach ($tables as $tableName => $table) {
            /* @var $table \Doctrine\DBAL\Schema\Table */
            if ($this->_sm->getDatabasePlatform()->supportsForeignKeyConstraints()) {
                $foreignKeys = $table->getForeignKeys();
            } else {
                $foreignKeys = array();
            }

            $allForeignKeyColumns = array();
            foreach ($foreignKeys as $foreignKey) {
                $allForeignKeyColumns = array_merge($allForeignKeyColumns, $foreignKey->getLocalColumns());
            }

            $pkColumns=array();
            if ($table->hasPrimaryKey()) {
                $pkColumns = $table->getPrimaryKey()->getColumns();
                sort($pkColumns);
            }

            sort($allForeignKeyColumns);

            if ($pkColumns == $allForeignKeyColumns && count($foreignKeys) == 2) {
                $this->manyToManyTables[$tableName] = $table;
            } else {
                // lower-casing is necessary because of Oracle Uppercase Tablenames,
                // assumption is lower-case + underscore separated.
                $className = $this->getClassNameForTable($tableName);
                $this->tables[$tableName] = $table;
                $this->classToTableNames[$className] = $tableName;
            }
        }
    }

3. Find the method loadMetadataForClass in the same file. Modify the code as stated below.
Find the code stated below:

try {
   $primaryKeyColumns = $this->tables[$tableName]->getPrimaryKey()->getColumns();
} catch(SchemaException $e) {
    $primaryKeyColumns = array();
}

Modify it like this:

try {
     $primaryKeyColumns = ($this->tables[$tableName]->hasPrimaryKey())?$this->tables[$tableName]->getPrimaryKey()->getColumns():array();
} catch(SchemaException $e) {
     $primaryKeyColumns = array();
}

The above solution creates mappings(xml/yml/annotation) even for tables that don't have a primary key.