Archive Project

# Conflicts:
#	.gitignore

alembic_data/ops/update_row.py

@@ -0,0 +1,57 @@
+from typing import Any, Mapping, List
+
+import sqlalchemy
+from alembic.autogenerate import renderers
+from alembic.autogenerate.api import AutogenContext
+from alembic.operations import Operations, MigrateOperation
+
+__all__ = ["UpdateRowOp"]
+
+from sqlalchemy.sql.elements import ColumnClause
+
+
+@Operations.register_operation("update_row")
+class UpdateRowOp(MigrateOperation):
+    """This `MigrationOperation` updates rows in a database table."""
+
+    def __init__(self, table_name: str, new_values: Mapping[str, Any], old_values: Mapping[str, Any]) -> None:
+        """Creates a new `InsertRowOp`.
+
+        :param table_name: The name of the table to update values in.
+        :param new_values: The new values to update in the table. Keys must correspond to column names in the table and
+                           values to their values.
+        :param old_values: The old values used to identify the row that should be updated.
+        """
+        self.table_name = table_name
+        self.new_values = new_values
+        self.old_values = old_values
+
+    @classmethod
+    def update_row(cls, operations: Operations, table_name: str, new_values: Mapping[str, Any],
+                   old_values: Mapping[str, Any]):
+        """Factory method for `UpdateRowOp`."""
+        op = UpdateRowOp(table_name, new_values, old_values)
+        return operations.invoke(op)
+
+    def reverse(self) -> MigrateOperation:
+        """Reverses the update operation by reverting back to the old values."""
+        return UpdateRowOp(self.table_name, self.old_values, self.new_values)
+
+
+@Operations.implementation_for(UpdateRowOp)
+def update_row(operations: Operations, operation: UpdateRowOp) -> None:
+    columns: List[ColumnClause] = [sqlalchemy.column(key) for key in operation.values.keys()]
+    table = sqlalchemy.table(operation.table_name, *columns)
+    where_clauses = [table.columns[key] == value for (key, value) in operation.old_values.items()]
+    operations.execute(
+        table.update().where(*where_clauses).values(**operation.new_values)
+    )
+
+
+@renderers.dispatch_for(UpdateRowOp)
+def render_update_row(autogen_context: AutogenContext, op: UpdateRowOp) -> str:
+    return "op.update_row(%r, **%r, **%r)" % (
+        op.table_name,
+        op.new_values,
+        op.old_values
+    )