# yii\db\mssql

> 11 classes of the yii\db\mssql namespace.

[API reference](/docs/api/index.md) › [yii](/docs/api/yii/index.md) › [db](/docs/api/yii/db/index.md) › mssql

## Namespaces

| Namespace | Types |
| --- | --- |
| [`yii\db\mssql\conditions`](/docs/api/yii/db/mssql/conditions/index.md) | 2 |

## Classes

| Class | Summary |
| --- | --- |
| [`ColumnSchema`](/docs/api/yii/db/mssql/columnschema/index.md) | Represents the metadata of a column in a Microsoft SQL Server database table. |
| [`ColumnSchemaBuilder`](/docs/api/yii/db/mssql/columnschemabuilder/index.md) | ColumnSchemaBuilder is the schema builder for MSSQL databases. |
| [`Command`](/docs/api/yii/db/mssql/command/index.md) | Command represents an MSSQL SQL statement to be executed against a database. |
| [`DBLibPDO`](/docs/api/yii/db/mssql/dblibpdo/index.md) | This is an extension of the default PDO class of DBLIB drivers. |
| [`PDO`](/docs/api/yii/db/mssql/pdo/index.md) | This is an extension of the default PDO class of MSSQL and DBLIB drivers. |
| [`QueryBuilder`](/docs/api/yii/db/mssql/querybuilder/index.md) | QueryBuilder is the query builder for MS SQL Server databases (version 2019 and above). |
| [`Quoter`](/docs/api/yii/db/mssql/quoter/index.md) | Provides connection-free helpers for quoting MSSQL values and identifiers when building SQL. |
| [`RowVersionBehavior`](/docs/api/yii/db/mssql/rowversionbehavior/index.md) | Refreshes a server-managed `rowversion` optimistic lock attribute from the database after each write. |
| [`Schema`](/docs/api/yii/db/mssql/schema/index.md) | Schema is the class for retrieving metadata from MS SQL Server databases (version 2019 and above). |
| [`SqlsrvPDO`](/docs/api/yii/db/mssql/sqlsrvpdo/index.md) | This is an extension of the default PDO class of SQLSRV driver. |
| [`TableSchema`](/docs/api/yii/db/mssql/tableschema/index.md) | TableSchema represents the metadata of a database table. |