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"""
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MySQL database specific implementations of changeset classes.
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"""
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from sqlalchemy.databases import mysql as sa_base
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from sqlalchemy import types as sqltypes
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from migrate import exceptions
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from migrate.changeset import ansisql, SQLA_06
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if not SQLA_06:
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MySQLSchemaGenerator = sa_base.MySQLSchemaGenerator
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else:
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MySQLSchemaGenerator = sa_base.MySQLDDLCompiler
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class MySQLColumnGenerator(MySQLSchemaGenerator, ansisql.ANSIColumnGenerator):
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pass
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class MySQLColumnDropper(ansisql.ANSIColumnDropper):
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pass
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class MySQLSchemaChanger(MySQLSchemaGenerator, ansisql.ANSISchemaChanger):
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def visit_column(self, delta):
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table = delta.table
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colspec = self.get_column_specification(delta.result_column)
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if delta.result_column.autoincrement:
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primary_keys = [c for c in table.primary_key.columns
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if (c.autoincrement and
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isinstance(c.type, sqltypes.Integer) and
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not c.foreign_keys)]
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if primary_keys:
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first = primary_keys.pop(0)
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if first.name == delta.current_name:
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colspec += " AUTO_INCREMENT"
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old_col_name = self.preparer.quote(delta.current_name, table.quote)
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self.start_alter_table(table)
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self.append("CHANGE COLUMN %s " % old_col_name)
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self.append(colspec)
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self.execute()
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def visit_index(self, param):
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# If MySQL can do this, I can't find how
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raise exceptions.NotSupportedError("MySQL cannot rename indexes")
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class MySQLConstraintGenerator(ansisql.ANSIConstraintGenerator):
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pass
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if SQLA_06:
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class MySQLConstraintDropper(MySQLSchemaGenerator, ansisql.ANSIConstraintDropper):
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def visit_migrate_check_constraint(self, *p, **k):
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raise exceptions.NotSupportedError("MySQL does not support CHECK"
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" constraints, use triggers instead.")
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else:
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class MySQLConstraintDropper(ansisql.ANSIConstraintDropper):
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def visit_migrate_primary_key_constraint(self, constraint):
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self.start_alter_table(constraint)
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self.append("DROP PRIMARY KEY")
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self.execute()
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def visit_migrate_foreign_key_constraint(self, constraint):
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self.start_alter_table(constraint)
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self.append("DROP FOREIGN KEY ")
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constraint.name = self.get_constraint_name(constraint)
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self.append(self.preparer.format_constraint(constraint))
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self.execute()
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def visit_migrate_check_constraint(self, *p, **k):
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raise exceptions.NotSupportedError("MySQL does not support CHECK"
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" constraints, use triggers instead.")
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def visit_migrate_unique_constraint(self, constraint, *p, **k):
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self.start_alter_table(constraint)
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self.append('DROP INDEX ')
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constraint.name = self.get_constraint_name(constraint)
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self.append(self.preparer.format_constraint(constraint))
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self.execute()
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class MySQLDialect(ansisql.ANSIDialect):
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columngenerator = MySQLColumnGenerator
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columndropper = MySQLColumnDropper
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schemachanger = MySQLSchemaChanger
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constraintgenerator = MySQLConstraintGenerator
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constraintdropper = MySQLConstraintDropper
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