/django/db/backends/mysql/introspection.py
Python | 105 lines | 84 code | 9 blank | 12 comment | 3 complexity | 5b378bcfde83e7388092686a3c8ff325 MD5 | raw file
Possible License(s): BSD-3-Clause
- import re
- from .base import FIELD_TYPE
- from django.db.backends import BaseDatabaseIntrospection
- from django.utils import six
- foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")
- class DatabaseIntrospection(BaseDatabaseIntrospection):
- data_types_reverse = {
- FIELD_TYPE.BLOB: 'TextField',
- FIELD_TYPE.CHAR: 'CharField',
- FIELD_TYPE.DECIMAL: 'DecimalField',
- FIELD_TYPE.NEWDECIMAL: 'DecimalField',
- FIELD_TYPE.DATE: 'DateField',
- FIELD_TYPE.DATETIME: 'DateTimeField',
- FIELD_TYPE.DOUBLE: 'FloatField',
- FIELD_TYPE.FLOAT: 'FloatField',
- FIELD_TYPE.INT24: 'IntegerField',
- FIELD_TYPE.LONG: 'IntegerField',
- FIELD_TYPE.LONGLONG: 'BigIntegerField',
- FIELD_TYPE.SHORT: 'IntegerField',
- FIELD_TYPE.STRING: 'CharField',
- FIELD_TYPE.TIMESTAMP: 'DateTimeField',
- FIELD_TYPE.TINY: 'IntegerField',
- FIELD_TYPE.TINY_BLOB: 'TextField',
- FIELD_TYPE.MEDIUM_BLOB: 'TextField',
- FIELD_TYPE.LONG_BLOB: 'TextField',
- FIELD_TYPE.VAR_STRING: 'CharField',
- }
- def get_table_list(self, cursor):
- "Returns a list of table names in the current database."
- cursor.execute("SHOW TABLES")
- return [row[0] for row in cursor.fetchall()]
- def get_table_description(self, cursor, table_name):
- "Returns a description of the table, with the DB-API cursor.description interface."
- cursor.execute("SELECT * FROM %s LIMIT 1" % self.connection.ops.quote_name(table_name))
- return cursor.description
- def _name_to_index(self, cursor, table_name):
- """
- Returns a dictionary of {field_name: field_index} for the given table.
- Indexes are 0-based.
- """
- return dict([(d[0], i) for i, d in enumerate(self.get_table_description(cursor, table_name))])
- def get_relations(self, cursor, table_name):
- """
- Returns a dictionary of {field_index: (field_index_other_table, other_table)}
- representing all relationships to the given table. Indexes are 0-based.
- """
- my_field_dict = self._name_to_index(cursor, table_name)
- constraints = self.get_key_columns(cursor, table_name)
- relations = {}
- for my_fieldname, other_table, other_field in constraints:
- other_field_index = self._name_to_index(cursor, other_table)[other_field]
- my_field_index = my_field_dict[my_fieldname]
- relations[my_field_index] = (other_field_index, other_table)
- return relations
- def get_key_columns(self, cursor, table_name):
- """
- Returns a list of (column_name, referenced_table_name, referenced_column_name) for all
- key columns in given table.
- """
- key_columns = []
- cursor.execute("""
- SELECT column_name, referenced_table_name, referenced_column_name
- FROM information_schema.key_column_usage
- WHERE table_name = %s
- AND table_schema = DATABASE()
- AND referenced_table_name IS NOT NULL
- AND referenced_column_name IS NOT NULL""", [table_name])
- key_columns.extend(cursor.fetchall())
- return key_columns
- def get_primary_key_column(self, cursor, table_name):
- """
- Returns the name of the primary key column for the given table
- """
- for column in six.iteritems(self.get_indexes(cursor, table_name)):
- if column[1]['primary_key']:
- return column[0]
- return None
- def get_indexes(self, cursor, table_name):
- cursor.execute("SHOW INDEX FROM %s" % self.connection.ops.quote_name(table_name))
- # Do a two-pass search for indexes: on first pass check which indexes
- # are multicolumn, on second pass check which single-column indexes
- # are present.
- rows = list(cursor.fetchall())
- multicol_indexes = set()
- for row in rows:
- if row[3] > 1:
- multicol_indexes.add(row[2])
- indexes = {}
- for row in rows:
- if row[2] in multicol_indexes:
- continue
- indexes[row[4]] = {'primary_key': (row[2] == 'PRIMARY'), 'unique': not bool(row[1])}
- return indexes