58 lines
2.2 KiB
Python
58 lines
2.2 KiB
Python
from typing import Any, Mapping, List
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import sqlalchemy
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from alembic.autogenerate import renderers
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from alembic.autogenerate.api import AutogenContext
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from alembic.operations import Operations, MigrateOperation
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__all__ = ["UpdateRowOp"]
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from sqlalchemy.sql.elements import ColumnClause
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@Operations.register_operation("update_row")
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class UpdateRowOp(MigrateOperation):
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"""This `MigrationOperation` updates rows in a database table."""
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def __init__(self, table_name: str, new_values: Mapping[str, Any], old_values: Mapping[str, Any]) -> None:
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"""Creates a new `InsertRowOp`.
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:param table_name: The name of the table to update values in.
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:param new_values: The new values to update in the table. Keys must correspond to column names in the table and
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values to their values.
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:param old_values: The old values used to identify the row that should be updated.
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"""
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self.table_name = table_name
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self.new_values = new_values
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self.old_values = old_values
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@classmethod
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def update_row(cls, operations: Operations, table_name: str, new_values: Mapping[str, Any],
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old_values: Mapping[str, Any]):
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"""Factory method for `UpdateRowOp`."""
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op = UpdateRowOp(table_name, new_values, old_values)
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return operations.invoke(op)
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def reverse(self) -> MigrateOperation:
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"""Reverses the update operation by reverting back to the old values."""
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return UpdateRowOp(self.table_name, self.old_values, self.new_values)
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@Operations.implementation_for(UpdateRowOp)
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def update_row(operations: Operations, operation: UpdateRowOp) -> None:
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columns: List[ColumnClause] = [sqlalchemy.column(key) for key in operation.values.keys()]
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table = sqlalchemy.table(operation.table_name, *columns)
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where_clauses = [table.columns[key] == value for (key, value) in operation.old_values.items()]
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operations.execute(
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table.update().where(*where_clauses).values(**operation.new_values)
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)
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@renderers.dispatch_for(UpdateRowOp)
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def render_update_row(autogen_context: AutogenContext, op: UpdateRowOp) -> str:
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return "op.update_row(%r, **%r, **%r)" % (
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op.table_name,
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op.new_values,
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op.old_values
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)
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