"""Spanner metadata queries using INFORMATION_SCHEMA."""
from typing import TYPE_CHECKING, ClassVar
from mypy_extensions import mypyc_attr
from sqlspec.driver import SyncDataDictionaryBase
from sqlspec.typing import ColumnMetadata, ForeignKeyMetadata, IndexMetadata, TableMetadata, VersionInfo
__all__ = ("SpannerDataDictionary",)
if TYPE_CHECKING:
from sqlspec.adapters.spanner.driver import SpannerSyncDriver
[docs]
@mypyc_attr(allow_interpreted_subclasses=True, native_class=False)
class SpannerDataDictionary(SyncDataDictionaryBase):
"""Fetch table, column, and index metadata from Spanner."""
dialect: ClassVar[str] = "spanner"
[docs]
def __init__(self) -> None:
super().__init__()
[docs]
def get_version(self, driver: "SpannerSyncDriver") -> "VersionInfo | None":
"""Get Spanner version information.
Args:
driver: Spanner driver instance.
Returns:
None since Spanner does not expose version information.
"""
_ = driver
return None
[docs]
def get_feature_flag(self, driver: "SpannerSyncDriver", feature: str) -> bool:
"""Check if Spanner supports a specific feature.
Args:
driver: Spanner driver instance.
feature: Feature name to check.
Returns:
True if feature is supported, False otherwise.
"""
_ = driver
return self.resolve_feature_flag(feature, None)
[docs]
def get_optimal_type(self, driver: "SpannerSyncDriver", type_category: str) -> str:
"""Get optimal Spanner type for a category.
Args:
driver: Spanner driver instance.
type_category: Type category.
Returns:
Spanner-specific type name.
"""
_ = driver
return self.get_dialect_config().get_optimal_type(type_category)
[docs]
def get_tables(self, driver: "SpannerSyncDriver", schema: "str | None" = None) -> "list[TableMetadata]":
"""Get tables using INFORMATION_SCHEMA."""
schema_name = self.resolve_schema(schema)
self._log_schema_introspect(driver, schema_name=schema_name, table_name=None, operation="tables")
return driver.select(self.get_query("tables_by_schema"), schema_name=schema_name, schema_type=TableMetadata)
[docs]
def get_columns(
self, driver: "SpannerSyncDriver", table: "str | None" = None, schema: "str | None" = None
) -> "list[ColumnMetadata]":
"""Get column information for a table or schema."""
schema_name = self.resolve_schema(schema)
if table is None:
self._log_schema_introspect(driver, schema_name=schema_name, table_name=None, operation="columns")
return driver.select(
self.get_query("columns_by_schema"), schema_name=schema_name, schema_type=ColumnMetadata
)
self._log_table_describe(driver, schema_name=schema_name, table_name=table, operation="columns")
return driver.select(
self.get_query("columns_by_table"), table_name=table, schema_name=schema_name, schema_type=ColumnMetadata
)
[docs]
def get_indexes(
self, driver: "SpannerSyncDriver", table: "str | None" = None, schema: "str | None" = None
) -> "list[IndexMetadata]":
"""Get index metadata for a table or schema."""
schema_name = self.resolve_schema(schema)
if table is None:
self._log_schema_introspect(driver, schema_name=schema_name, table_name=None, operation="indexes")
return driver.select(
self.get_query("indexes_by_schema"), schema_name=schema_name, schema_type=IndexMetadata
)
self._log_table_describe(driver, schema_name=schema_name, table_name=table, operation="indexes")
return driver.select(
self.get_query("indexes_by_table"), table_name=table, schema_name=schema_name, schema_type=IndexMetadata
)
[docs]
def get_foreign_keys(
self, driver: "SpannerSyncDriver", table: "str | None" = None, schema: "str | None" = None
) -> "list[ForeignKeyMetadata]":
"""Get foreign key metadata."""
schema_name = self.resolve_schema(schema)
if table is None:
self._log_schema_introspect(driver, schema_name=schema_name, table_name=None, operation="foreign_keys")
return driver.select(
self.get_query("foreign_keys_by_schema"), schema_name=schema_name, schema_type=ForeignKeyMetadata
)
self._log_table_describe(driver, schema_name=schema_name, table_name=table, operation="foreign_keys")
return driver.select(
self.get_query("foreign_keys_by_table"),
table_name=table,
schema_name=schema_name,
schema_type=ForeignKeyMetadata,
)
