pymssql

Sync SQL Server adapter using pymssql and FreeTDS. It uses pyformat parameters (%s and %(name)s) and exposes sync SQLSpec config, driver, pooling, data dictionary, migration, and extension store integrations.

Configuration

class sqlspec.adapters.pymssql.PymssqlConfig

Bases: SyncDatabaseConfig[Connection, PymssqlConnectionPool, PymssqlDriver]

Configuration for pymssql synchronous connections.

driver_type

alias of PymssqlDriver

connection_type

alias of Connection

migration_tracker_type

alias of PymssqlSyncMigrationTracker

__init__(*, connection_config=None, connection_instance=None, migration_config=None, statement_config=None, driver_features=None, bind_key=None, extension_config=None, observability_config=None, **kwargs)

create_connection()

Create a database connection.

Return type:

Connection

get_signature_namespace()

Get the signature namespace for this database configuration.

Returns a dictionary of type names to objects (classes, functions, or other callables) that should be registered with Litestar's signature namespace to prevent serialization attempts on database-specific structures.

Return type:

dict[str, typing.Any]

Returns:

Dictionary mapping type names to objects.

get_event_runtime_hints()

Return default event runtime hints for this configuration.

Return type:

EventRuntimeHints

Connection Parameters

class sqlspec.adapters.pymssql.config.PymssqlConnectionParams

Bases: TypedDict

pymssql connection parameters.

Driver Features

class sqlspec.adapters.pymssql.config.PymssqlDriverFeatures

Bases: TypedDict

pymssql driver feature flags.

json_serializer: Custom JSON serializer function.

Defaults to sqlspec.utils.serializers.to_json.

json_deserializer: Custom JSON deserializer function.

Defaults to sqlspec.utils.serializers.from_json.

on_connection_create: Callback executed when a connection is created.

Receives the raw pymssql connection for low-level driver configuration. Runs after connection creation.

enable_events: Enable database event channel support. events_backend: Event channel backend selection.

Driver

class sqlspec.adapters.pymssql.PymssqlDriver

Bases: SyncDriverAdapterBase

SQL Server database driver using pymssql.

__init__(connection, statement_config=None, driver_features=None)

Initialize driver adapter with connection and configuration.

Parameters:

• connection (Connection) -- Database connection instance

• statement_config (StatementConfig | None) -- Statement configuration for the driver

• driver_features (dict[str, typing.Any] | None) -- Driver-specific features like extensions, secrets, and connection callbacks

• observability -- Optional runtime handling lifecycle hooks, observers, and spans

dispatch_execute(cursor, statement)

Execute a single SQL statement.

Must be implemented by each driver for database-specific execution logic.

Parameters:

• cursor (Cursor) -- Database cursor/connection object

• statement (SQL) -- SQL statement object with all necessary data and configuration

Return type:

ExecutionResult

Returns:

ExecutionResult with execution data

dispatch_execute_many(cursor, statement)

Execute SQL with multiple parameter sets (executemany).

Must be implemented by each driver for database-specific executemany logic.

Parameters:

• cursor (Cursor) -- Database cursor/connection object

• statement (SQL) -- SQL statement object with all necessary data and configuration

Return type:

ExecutionResult

Returns:

ExecutionResult with execution data for the many operation

dispatch_execute_script(cursor, statement)

Execute a SQL script containing multiple statements.

Default implementation splits the script and executes statements individually. Drivers can override for database-specific script execution methods.

Parameters:

• cursor (Cursor) -- Database cursor/connection object

• statement (SQL) -- SQL statement object with all necessary data and configuration

Return type:

ExecutionResult

Returns:

ExecutionResult with script execution data including statement counts

begin()

Begin a database transaction on the current connection.

Return type:

None

commit()

Commit the current transaction on the current connection.

Return type:

None

rollback()

Rollback the current transaction on the current connection.

Return type:

None

with_cursor(connection)

Create and return a context manager for cursor acquisition and cleanup.

Returns a context manager that yields a cursor for database operations. Concrete implementations handle database-specific cursor creation and cleanup.

Return type:

PymssqlCursor

handle_database_exceptions()

Handle database-specific exceptions and wrap them appropriately.

Return type:

PymssqlExceptionHandler

Returns:

Exception handler with deferred exception pattern for mypyc compatibility. The handler stores mapped exceptions in pending_exception rather than raising from __exit__ to avoid ABI boundary violations.

property data_dictionary: PymssqlSyncDataDictionary

Get the data dictionary for this driver.

Returns:

Data dictionary instance for metadata queries

collect_rows(cursor, fetched)

Collect rows from cursor after fetchall for the direct execution path.

Adapters should override this method to provide optimized row collection that bypasses full dispatch_execute overhead.

Parameters:

• cursor (Cursor) -- Database cursor with description metadata.

• fetched (list[typing.Any]) -- Rows returned from cursor.fetchall().

Return type:

tuple[list[typing.Any], list[str], int]

Returns:

Tuple of (data, column_names, row_count).

Raises:

NotImplementedError -- If the adapter does not implement this method.

resolve_rowcount(cursor)

Resolve the number of affected rows from cursor for the direct execution path.

Adapters should override this method to provide optimized rowcount resolution that bypasses full dispatch_execute overhead.

Parameters:

cursor (Cursor) -- Database cursor with rowcount metadata.

Return type:

int

Returns:

Number of affected rows, or 0 when unknown.

Raises:

NotImplementedError -- If the adapter does not implement this method.

Connection Pool

class sqlspec.adapters.pymssql.PymssqlConnectionPool

Bases: object

Thread-local connection manager for pymssql.

__init__(connection_parameters, recycle_seconds=86400, health_check_interval=30.0, on_connection_create=None)

Initialize the thread-local connection manager.

Parameters:

• connection_parameters -- pymssql connection parameters

• recycle_seconds -- Connection recycle time in seconds (default 24h)

• health_check_interval -- Seconds of idle time before running health check

• on_connection_create -- Callback executed when connection is created

get_connection()

Get a thread-local connection.

Return type:

Generator[Connection, None, None]

Data Dictionary

class sqlspec.adapters.pymssql.data_dictionary.PymssqlSyncDataDictionary

Bases: _MssqlDataDictionaryMixin, SyncDataDictionaryBase

MSSQL sync data dictionary.

dialect: ClassVar[str] = 'mssql'

Dialect identifier. Must be defined by subclasses as a class attribute.

__init__()

get_version(driver)

Get SQL Server version information.

Return type:

MssqlVersionInfo | None

get_feature_flag(driver, feature)

Check whether SQL Server supports a feature.

Return type:

bool

get_optimal_type(driver, type_category)

Get optimal SQL Server type for a category.

Return type:

str

get_tables(driver, schema=None)

Get tables sorted by dependency order with catalog fallback.

Return type:

list[TableMetadata]

get_columns(driver, table=None, schema=None)

Get column information for a table or schema.

Return type:

list[ColumnMetadata]

get_indexes(driver, table=None, schema=None)

Get index metadata for a table or schema.

Return type:

list[IndexMetadata]

get_foreign_keys(driver, table=None, schema=None)

Get foreign key metadata.

Return type:

list[ForeignKeyMetadata]

Migrations

class sqlspec.adapters.pymssql.migrations.PymssqlSyncMigrationTracker

Bases: PymssqlMigrationTrackerMixin, SyncMigrationTracker

T-SQL sync migration tracker.

ensure_tracking_table(driver)

Create the migration tracking table if it does not exist.

Return type:

None

record_migration(driver, version, description, execution_time_ms, checksum)

Record a successfully applied migration with T-SQL-compatible metadata.

Return type:

None