无主键实体的Symfony原理模型

Question

在重新构建web应用程序时，我正在使用遗留数据库。我想使用Symfony2.x，它显然具有Doctrine作为ORM。

我有大约50个没有主键的(mysql)表。当我尝试生成模型时，它不允许我这样做，并抛出一个异常"No Primary Key on ... table“。

我必须在表上有主键才能使用Doctrine吗?或者有什么方法可以绕过它吗？

任何帮助都是最好的。

谢谢。

Answer 1

原理要求每个实体类都有一个标识符/主键。

看看这个页面：http://www.doctrine-project.org/docs/orm/2.0/en/reference/basic-mapping.html#identifiers-primary-keys

Answer 2

Doctrine要求有一个标识符/主键。看看这个页面：http://www.doctrine-project.org/docs/orm/2.0/en/reference/basic-mapping.html#identifiers-primary-keys

但是有一种方法可以从没有主键的表中生成映射和实体。没有主键的表是一种不常见且糟糕的数据库设计，但在遗留数据库的情况下也存在这种情况。

解决方案

注释：下面的所有参考文献都指的是Doctrin2.0

找到文件DatabaseDriver.php (在Doctrine/ORM/Mapping/Driver/DatabaseDriver.php)

• Find中为reverseEngineerMappingFromDatabase.

1. 按照下面的说明修改代码。

原始代码是：

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;
            }
        }
    }

修改后的代码为：

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;
            }
        }
    }

在同一文件中查找loadMetadataForClass方法

1. 。按照下面的说明修改代码。

查找下面陈述的代码：

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

如下所示修改：

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

即使对于没有主键的表，上面的解决方案也会创建映射(xml/yml/注解)。