"""PostgreSQL-specific data dictionary for metadata queries via asyncpg."""
from typing import TYPE_CHECKING, ClassVar
from sqlspec.driver import AsyncDataDictionaryBase
from sqlspec.typing import ColumnMetadata, ForeignKeyMetadata, IndexMetadata, TableMetadata, VersionInfo
if TYPE_CHECKING:
from sqlspec.adapters.asyncpg.driver import AsyncpgDriver
__all__ = ("AsyncpgDataDictionary",)
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class AsyncpgDataDictionary(AsyncDataDictionaryBase):
"""PostgreSQL-specific async data dictionary."""
dialect: ClassVar[str] = "postgres"
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def __init__(self) -> None:
super().__init__()
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def resolve_schema(self, schema: "str | None") -> "str | None":
"""Return a schema name using dialect defaults when missing."""
if schema is not None:
return schema
return self.get_dialect_config().default_schema
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async def get_version(self, driver: "AsyncpgDriver") -> "VersionInfo | None":
"""Get PostgreSQL database version information.
Args:
driver: Async database driver instance.
Returns:
PostgreSQL version information or None if detection fails.
"""
driver_id = id(driver)
# Inline cache check to avoid cross-module method call that causes mypyc segfault
if driver_id in self._version_fetch_attempted:
return self._version_cache.get(driver_id)
# Not cached, fetch from database
version_value = await driver.select_value_or_none(self.get_query("version"))
if not version_value:
self._log_version_unavailable(type(self).dialect, "missing")
self.cache_version(driver_id, None)
return None
config = self.get_dialect_config()
version_info = self.parse_version_with_pattern(config.version_pattern, str(version_value))
if version_info is None:
self._log_version_unavailable(type(self).dialect, "parse_failed")
self.cache_version(driver_id, None)
return None
self._log_version_detected(type(self).dialect, version_info)
self.cache_version(id(driver), version_info)
return version_info
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async def get_feature_flag(self, driver: "AsyncpgDriver", feature: str) -> bool:
"""Check if PostgreSQL database supports a specific feature.
Args:
driver: Async database driver instance.
feature: Feature name to check.
Returns:
True if feature is supported, False otherwise.
"""
version_info = await self.get_version(driver)
return self.resolve_feature_flag(feature, version_info)
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async def get_optimal_type(self, driver: "AsyncpgDriver", type_category: str) -> str:
"""Get optimal PostgreSQL type for a category.
Args:
driver: Async database driver instance.
type_category: Type category.
Returns:
PostgreSQL-specific type name.
"""
config = self.get_dialect_config()
version_info = await self.get_version(driver)
if type_category == "json":
jsonb_version = config.get_feature_version("supports_jsonb")
json_version = config.get_feature_version("supports_json")
if version_info and jsonb_version and version_info >= jsonb_version:
return "JSONB"
if version_info and json_version and version_info >= json_version:
return "JSON"
return "TEXT"
return config.get_optimal_type(type_category)
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def list_available_features(self) -> "list[str]":
"""List available feature flags for this dialect."""
config = self.get_dialect_config()
features = set(config.feature_flags.keys()) | set(config.feature_versions.keys())
return sorted(features)
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async def get_tables(self, driver: "AsyncpgDriver", schema: "str | None" = None) -> "list[TableMetadata]":
"""Get tables sorted by topological dependency order using Recursive CTE."""
schema_name = self.resolve_schema(schema)
self._log_schema_introspect(driver, schema_name=schema_name, table_name=None, operation="tables")
return await driver.select(
self.get_query("tables_by_schema"), schema_name=schema_name, schema_type=TableMetadata
)
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async def get_columns(
self, driver: "AsyncpgDriver", 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 await 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 await driver.select(
self.get_query("columns_by_table"), schema_name=schema_name, table_name=table, schema_type=ColumnMetadata
)
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async def get_indexes(
self, driver: "AsyncpgDriver", 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 await 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 await driver.select(
self.get_query("indexes_by_table"), schema_name=schema_name, table_name=table, schema_type=IndexMetadata
)
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async def get_foreign_keys(
self, driver: "AsyncpgDriver", 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 await 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 await driver.select(
self.get_query("foreign_keys_by_table"),
schema_name=schema_name,
table_name=table,
schema_type=ForeignKeyMetadata,
)
