"""This module defines specific functions for MySQL dialect."""
from sqlalchemy import text
from sqlalchemy.dialects.mysql.base import ischema_names as _mysql_ischema_names
from sqlalchemy.ext.compiler import compiles
from sqlalchemy.sql.sqltypes import NullType
from geoalchemy2 import functions
from geoalchemy2.admin.dialects.common import _check_spatial_type
from geoalchemy2.admin.dialects.common import _spatial_idx_name
from geoalchemy2.admin.dialects.common import compile_bin_literal
from geoalchemy2.admin.dialects.common import setup_create_drop
from geoalchemy2.types import Geography
from geoalchemy2.types import Geometry
# Register Geometry, Geography and Raster to SQLAlchemy's reflection subsystems.
_mysql_ischema_names["geometry"] = Geometry
_mysql_ischema_names["point"] = Geometry
_mysql_ischema_names["linestring"] = Geometry
_mysql_ischema_names["polygon"] = Geometry
_mysql_ischema_names["multipoint"] = Geometry
_mysql_ischema_names["multilinestring"] = Geometry
_mysql_ischema_names["multipolygon"] = Geometry
_mysql_ischema_names["geometrycollection"] = Geometry
_POSSIBLE_TYPES = [
"geometry",
"point",
"linestring",
"polygon",
"multipoint",
"multilinestring",
"multipolygon",
"geometrycollection",
]
[docs]
def reflect_geometry_column(inspector, table, column_info):
"""Reflect a column of type Geometry with Postgresql dialect."""
if not isinstance(column_info.get("type"), Geometry | NullType):
return
column_name = column_info.get("name")
schema = table.schema or inspector.default_schema_name
select_srid = "-1, " if inspector.dialect.name == "mariadb" else "SRS_ID, "
# Check geometry type, SRID and if the column is nullable
geometry_type_query = f"""SELECT DATA_TYPE, {select_srid}IS_NULLABLE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = '{table.name}' and COLUMN_NAME = '{column_name}'"""
if schema is not None:
geometry_type_query += f""" and table_schema = '{schema}'"""
geometry_type, srid, nullable_str = inspector.bind.execute(text(geometry_type_query)).one()
is_nullable = str(nullable_str).lower() == "yes"
if geometry_type not in _POSSIBLE_TYPES:
return # pragma: no cover
# Check if the column has spatial index
has_index_query = f"""SELECT DISTINCT
INDEX_TYPE
FROM INFORMATION_SCHEMA.STATISTICS
WHERE TABLE_NAME = '{table.name}' and COLUMN_NAME = '{column_name}'"""
if schema is not None:
has_index_query += f""" and TABLE_SCHEMA = '{schema}'"""
spatial_index_res = inspector.bind.execute(text(has_index_query)).scalar()
spatial_index = str(spatial_index_res).lower() == "spatial"
# Set attributes
column_info["type"] = Geometry(
geometry_type=geometry_type.upper(),
srid=srid,
spatial_index=spatial_index,
nullable=is_nullable,
_spatial_index_reflected=True,
)
[docs]
def before_cursor_execute(conn, cursor, statement, parameters, context, executemany, convert=True): # noqa: D417
"""Event handler to cast the parameters properly.
Args:
convert (bool): Trigger the conversion.
"""
if convert:
if isinstance(parameters, tuple | list):
parameters = tuple(x.tobytes() if isinstance(x, memoryview) else x for x in parameters)
elif isinstance(parameters, dict):
for k in parameters:
if isinstance(parameters[k], memoryview):
parameters[k] = parameters[k].tobytes()
return statement, parameters
[docs]
def before_create(table, bind, **kw):
"""Handle spatial indexes during the before_create event."""
dialect, gis_cols, regular_cols = setup_create_drop(table, bind)
# Remove the spatial indexes from the table metadata because they should not be
# created during the table.create() step since the associated columns do not exist
# at this time.
table.info["_after_create_indexes"] = []
current_indexes = set(table.indexes)
for idx in current_indexes:
for col in table.info["_saved_columns"]:
if (_check_spatial_type(col.type, Geometry, dialect)) and col in idx.columns.values():
table.indexes.remove(idx)
if idx.name != _spatial_idx_name(table.name, col.name) or not getattr(
col.type, "spatial_index", False
):
table.info["_after_create_indexes"].append(idx)
table.columns = table.info.pop("_saved_columns")
[docs]
def after_create(table, bind, **kw):
"""Handle spatial indexes during the after_create event."""
# Restore original column list including managed Geometry columns
dialect = bind.dialect
# table.columns = table.info.pop("_saved_columns")
for col in table.columns:
# Add spatial indices for the Geometry and Geography columns
if (
_check_spatial_type(col.type, (Geometry, Geography), dialect)
and col.type.spatial_index is True
and col.computed is None
and not [i for i in table.indexes if col in i.columns.values()]
):
sql = f"ALTER TABLE {table.name} ADD SPATIAL INDEX({col.name});"
q = text(sql)
bind.execute(q)
for idx in table.info.pop("_after_create_indexes"):
table.indexes.add(idx)
def before_drop(table, bind, **kw):
return
def after_drop(table, bind, **kw):
return
_MYSQL_FUNCTIONS = {"ST_AsEWKB": "ST_AsBinary", "ST_SetSRID": "ST_SRID"}
def _compiles_mysql(cls, fn):
def _compile_mysql(element, compiler, **kw):
return f"{fn}({compiler.process(element.clauses, **kw)})"
compiles(getattr(functions, cls), "mysql")(_compile_mysql)
[docs]
def register_mysql_mapping(mapping):
"""Register compilation mappings for the given functions.
Args:
mapping: Should have the following form::
{
"function_name_1": "mysql_function_name_1",
"function_name_2": "mysql_function_name_2",
...
}
"""
for cls, fn in mapping.items():
_compiles_mysql(cls, fn)
register_mysql_mapping(_MYSQL_FUNCTIONS)
def _compile_GeomFromText_MySql(element, compiler, **kw):
identifier = "ST_GeomFromText"
compiled = compiler.process(element.clauses, **kw)
srid = element.type.srid
if srid > 0:
return f"{identifier}({compiled}, {srid})"
else:
return f"{identifier}({compiled})"
def _compile_GeomFromWKB_MySql(element, compiler, **kw):
# Store the SRID
clauses = list(element.clauses)
try:
srid = clauses[1].value
except (IndexError, TypeError, ValueError):
srid = element.type.srid
if kw.get("literal_binds", False):
wkb_clause = compile_bin_literal(clauses[0])
prefix = "unhex("
suffix = ")"
else:
wkb_clause = clauses[0]
prefix = ""
suffix = ""
compiled = compiler.process(wkb_clause, **kw)
if srid > 0:
return f"{element.identifier}({prefix}{compiled}{suffix}, {srid})"
else:
return f"{element.identifier}({prefix}{compiled}{suffix})"
@compiles(functions.ST_GeomFromText, "mysql") # type: ignore
def _MySQL_ST_GeomFromText(element, compiler, **kw):
return _compile_GeomFromText_MySql(element, compiler, **kw)
@compiles(functions.ST_GeomFromEWKT, "mysql") # type: ignore
def _MySQL_ST_GeomFromEWKT(element, compiler, **kw):
return _compile_GeomFromText_MySql(element, compiler, **kw)
@compiles(functions.ST_GeomFromWKB, "mysql") # type: ignore
def _MySQL_ST_GeomFromWKB(element, compiler, **kw):
return _compile_GeomFromWKB_MySql(element, compiler, **kw)
@compiles(functions.ST_GeomFromEWKB, "mysql") # type: ignore
def _MySQL_ST_GeomFromEWKB(element, compiler, **kw):
return _compile_GeomFromWKB_MySql(element, compiler, **kw)
