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Diffstat (limited to '.venv/lib/python3.12/site-packages/alembic/ddl/sqlite.py')
| -rw-r--r-- | .venv/lib/python3.12/site-packages/alembic/ddl/sqlite.py | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/alembic/ddl/sqlite.py b/.venv/lib/python3.12/site-packages/alembic/ddl/sqlite.py new file mode 100644 index 00000000..7c6fb20c --- /dev/null +++ b/.venv/lib/python3.12/site-packages/alembic/ddl/sqlite.py @@ -0,0 +1,237 @@ +# mypy: allow-untyped-defs, allow-incomplete-defs, allow-untyped-calls +# mypy: no-warn-return-any, allow-any-generics + +from __future__ import annotations + +import re +from typing import Any +from typing import Dict +from typing import Optional +from typing import TYPE_CHECKING +from typing import Union + +from sqlalchemy import cast +from sqlalchemy import Computed +from sqlalchemy import JSON +from sqlalchemy import schema +from sqlalchemy import sql + +from .base import alter_table +from .base import ColumnName +from .base import format_column_name +from .base import format_table_name +from .base import RenameTable +from .impl import DefaultImpl +from .. import util +from ..util.sqla_compat import compiles + +if TYPE_CHECKING: + from sqlalchemy.engine.reflection import Inspector + from sqlalchemy.sql.compiler import DDLCompiler + from sqlalchemy.sql.elements import Cast + from sqlalchemy.sql.elements import ClauseElement + from sqlalchemy.sql.schema import Column + from sqlalchemy.sql.schema import Constraint + from sqlalchemy.sql.schema import Table + from sqlalchemy.sql.type_api import TypeEngine + + from ..operations.batch import BatchOperationsImpl + + +class SQLiteImpl(DefaultImpl): + __dialect__ = "sqlite" + + transactional_ddl = False + """SQLite supports transactional DDL, but pysqlite does not: + see: http://bugs.python.org/issue10740 + """ + + def requires_recreate_in_batch( + self, batch_op: BatchOperationsImpl + ) -> bool: + """Return True if the given :class:`.BatchOperationsImpl` + would need the table to be recreated and copied in order to + proceed. + + Normally, only returns True on SQLite when operations other + than add_column are present. + + """ + for op in batch_op.batch: + if op[0] == "add_column": + col = op[1][1] + if isinstance( + col.server_default, schema.DefaultClause + ) and isinstance(col.server_default.arg, sql.ClauseElement): + return True + elif ( + isinstance(col.server_default, Computed) + and col.server_default.persisted + ): + return True + elif op[0] not in ("create_index", "drop_index"): + return True + else: + return False + + def add_constraint(self, const: Constraint): + # attempt to distinguish between an + # auto-gen constraint and an explicit one + if const._create_rule is None: + raise NotImplementedError( + "No support for ALTER of constraints in SQLite dialect. " + "Please refer to the batch mode feature which allows for " + "SQLite migrations using a copy-and-move strategy." + ) + elif const._create_rule(self): + util.warn( + "Skipping unsupported ALTER for " + "creation of implicit constraint. " + "Please refer to the batch mode feature which allows for " + "SQLite migrations using a copy-and-move strategy." + ) + + def drop_constraint(self, const: Constraint): + if const._create_rule is None: + raise NotImplementedError( + "No support for ALTER of constraints in SQLite dialect. " + "Please refer to the batch mode feature which allows for " + "SQLite migrations using a copy-and-move strategy." + ) + + def compare_server_default( + self, + inspector_column: Column[Any], + metadata_column: Column[Any], + rendered_metadata_default: Optional[str], + rendered_inspector_default: Optional[str], + ) -> bool: + if rendered_metadata_default is not None: + rendered_metadata_default = re.sub( + r"^\((.+)\)$", r"\1", rendered_metadata_default + ) + + rendered_metadata_default = re.sub( + r"^\"?'(.+)'\"?$", r"\1", rendered_metadata_default + ) + + if rendered_inspector_default is not None: + rendered_inspector_default = re.sub( + r"^\((.+)\)$", r"\1", rendered_inspector_default + ) + + rendered_inspector_default = re.sub( + r"^\"?'(.+)'\"?$", r"\1", rendered_inspector_default + ) + + return rendered_inspector_default != rendered_metadata_default + + def _guess_if_default_is_unparenthesized_sql_expr( + self, expr: Optional[str] + ) -> bool: + """Determine if a server default is a SQL expression or a constant. + + There are too many assertions that expect server defaults to round-trip + identically without parenthesis added so we will add parens only in + very specific cases. + + """ + if not expr: + return False + elif re.match(r"^[0-9\.]$", expr): + return False + elif re.match(r"^'.+'$", expr): + return False + elif re.match(r"^\(.+\)$", expr): + return False + else: + return True + + def autogen_column_reflect( + self, + inspector: Inspector, + table: Table, + column_info: Dict[str, Any], + ) -> None: + # SQLite expression defaults require parenthesis when sent + # as DDL + if self._guess_if_default_is_unparenthesized_sql_expr( + column_info.get("default", None) + ): + column_info["default"] = "(%s)" % (column_info["default"],) + + def render_ddl_sql_expr( + self, expr: ClauseElement, is_server_default: bool = False, **kw + ) -> str: + # SQLite expression defaults require parenthesis when sent + # as DDL + str_expr = super().render_ddl_sql_expr( + expr, is_server_default=is_server_default, **kw + ) + + if ( + is_server_default + and self._guess_if_default_is_unparenthesized_sql_expr(str_expr) + ): + str_expr = "(%s)" % (str_expr,) + return str_expr + + def cast_for_batch_migrate( + self, + existing: Column[Any], + existing_transfer: Dict[str, Union[TypeEngine, Cast]], + new_type: TypeEngine, + ) -> None: + if ( + existing.type._type_affinity is not new_type._type_affinity + and not isinstance(new_type, JSON) + ): + existing_transfer["expr"] = cast( + existing_transfer["expr"], new_type + ) + + def correct_for_autogen_constraints( + self, + conn_unique_constraints, + conn_indexes, + metadata_unique_constraints, + metadata_indexes, + ): + self._skip_functional_indexes(metadata_indexes, conn_indexes) + + +@compiles(RenameTable, "sqlite") +def visit_rename_table( + element: RenameTable, compiler: DDLCompiler, **kw +) -> str: + return "%s RENAME TO %s" % ( + alter_table(compiler, element.table_name, element.schema), + format_table_name(compiler, element.new_table_name, None), + ) + + +@compiles(ColumnName, "sqlite") +def visit_column_name(element: ColumnName, compiler: DDLCompiler, **kw) -> str: + return "%s RENAME COLUMN %s TO %s" % ( + alter_table(compiler, element.table_name, element.schema), + format_column_name(compiler, element.column_name), + format_column_name(compiler, element.newname), + ) + + +# @compiles(AddColumn, 'sqlite') +# def visit_add_column(element, compiler, **kw): +# return "%s %s" % ( +# alter_table(compiler, element.table_name, element.schema), +# add_column(compiler, element.column, **kw) +# ) + + +# def add_column(compiler, column, **kw): +# text = "ADD COLUMN %s" % compiler.get_column_specification(column, **kw) +# need to modify SQLAlchemy so that the CHECK associated with a Boolean +# or Enum gets placed as part of the column constraints, not the Table +# see ticket 98 +# for const in column.constraints: +# text += compiler.process(AddConstraint(const)) +# return text |