275 lines
11 KiB
Python
275 lines
11 KiB
Python
import re
|
|
from collections import namedtuple
|
|
|
|
from django.db.backends.base.introspection import (
|
|
BaseDatabaseIntrospection, FieldInfo, TableInfo,
|
|
)
|
|
|
|
field_size_re = re.compile(r'^\s*(?:var)?char\s*\(\s*(\d+)\s*\)\s*$')
|
|
FieldInfo = namedtuple('FieldInfo', FieldInfo._fields + ('default',))
|
|
|
|
|
|
def get_field_size(name):
|
|
""" Extract the size number from a "varchar(11)" type name """
|
|
m = field_size_re.search(name)
|
|
return int(m.group(1)) if m else None
|
|
|
|
|
|
# This light wrapper "fakes" a dictionary interface, because some SQLite data
|
|
# types include variables in them -- e.g. "varchar(30)" -- and can't be matched
|
|
# as a simple dictionary lookup.
|
|
class FlexibleFieldLookupDict(object):
|
|
# Maps SQL types to Django Field types. Some of the SQL types have multiple
|
|
# entries here because SQLite allows for anything and doesn't normalize the
|
|
# field type; it uses whatever was given.
|
|
base_data_types_reverse = {
|
|
'bool': 'BooleanField',
|
|
'boolean': 'BooleanField',
|
|
'smallint': 'SmallIntegerField',
|
|
'smallint unsigned': 'PositiveSmallIntegerField',
|
|
'smallinteger': 'SmallIntegerField',
|
|
'int': 'IntegerField',
|
|
'integer': 'IntegerField',
|
|
'bigint': 'BigIntegerField',
|
|
'integer unsigned': 'PositiveIntegerField',
|
|
'decimal': 'DecimalField',
|
|
'real': 'FloatField',
|
|
'text': 'TextField',
|
|
'char': 'CharField',
|
|
'blob': 'BinaryField',
|
|
'date': 'DateField',
|
|
'datetime': 'DateTimeField',
|
|
'time': 'TimeField',
|
|
}
|
|
|
|
def __getitem__(self, key):
|
|
key = key.lower()
|
|
try:
|
|
return self.base_data_types_reverse[key]
|
|
except KeyError:
|
|
size = get_field_size(key)
|
|
if size is not None:
|
|
return ('CharField', {'max_length': size})
|
|
raise KeyError
|
|
|
|
|
|
class DatabaseIntrospection(BaseDatabaseIntrospection):
|
|
data_types_reverse = FlexibleFieldLookupDict()
|
|
|
|
def get_table_list(self, cursor):
|
|
"""
|
|
Returns a list of table and view names in the current database.
|
|
"""
|
|
# Skip the sqlite_sequence system table used for autoincrement key
|
|
# generation.
|
|
cursor.execute("""
|
|
SELECT name, type FROM sqlite_master
|
|
WHERE type in ('table', 'view') AND NOT name='sqlite_sequence'
|
|
ORDER BY name""")
|
|
return [TableInfo(row[0], row[1][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."
|
|
return [
|
|
FieldInfo(
|
|
info['name'],
|
|
info['type'],
|
|
None,
|
|
info['size'],
|
|
None,
|
|
None,
|
|
info['null_ok'],
|
|
info['default'],
|
|
) for info in self._table_info(cursor, table_name)
|
|
]
|
|
|
|
def column_name_converter(self, name):
|
|
"""
|
|
SQLite will in some cases, e.g. when returning columns from views and
|
|
subselects, return column names in 'alias."column"' format instead of
|
|
simply 'column'.
|
|
|
|
Affects SQLite < 3.7.15, fixed by http://www.sqlite.org/src/info/5526e0aa3c
|
|
"""
|
|
# TODO: remove when SQLite < 3.7.15 is sufficiently old.
|
|
# 3.7.13 ships in Debian stable as of 2014-03-21.
|
|
if self.connection.Database.sqlite_version_info < (3, 7, 15):
|
|
return name.split('.')[-1].strip('"')
|
|
else:
|
|
return 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.
|
|
"""
|
|
|
|
# Dictionary of relations to return
|
|
relations = {}
|
|
|
|
# Schema for this table
|
|
cursor.execute("SELECT sql FROM sqlite_master WHERE tbl_name = %s AND type = %s", [table_name, "table"])
|
|
try:
|
|
results = cursor.fetchone()[0].strip()
|
|
except TypeError:
|
|
# It might be a view, then no results will be returned
|
|
return relations
|
|
results = results[results.index('(') + 1:results.rindex(')')]
|
|
|
|
# Walk through and look for references to other tables. SQLite doesn't
|
|
# really have enforced references, but since it echoes out the SQL used
|
|
# to create the table we can look for REFERENCES statements used there.
|
|
for field_desc in results.split(','):
|
|
field_desc = field_desc.strip()
|
|
if field_desc.startswith("UNIQUE"):
|
|
continue
|
|
|
|
m = re.search('references (\S*) ?\(["|]?(.*)["|]?\)', field_desc, re.I)
|
|
if not m:
|
|
continue
|
|
table, column = [s.strip('"') for s in m.groups()]
|
|
|
|
if field_desc.startswith("FOREIGN KEY"):
|
|
# Find name of the target FK field
|
|
m = re.match('FOREIGN KEY\(([^\)]*)\).*', field_desc, re.I)
|
|
field_name = m.groups()[0].strip('"')
|
|
else:
|
|
field_name = field_desc.split()[0].strip('"')
|
|
|
|
cursor.execute("SELECT sql FROM sqlite_master WHERE tbl_name = %s", [table])
|
|
result = cursor.fetchall()[0]
|
|
other_table_results = result[0].strip()
|
|
li, ri = other_table_results.index('('), other_table_results.rindex(')')
|
|
other_table_results = other_table_results[li + 1:ri]
|
|
|
|
for other_desc in other_table_results.split(','):
|
|
other_desc = other_desc.strip()
|
|
if other_desc.startswith('UNIQUE'):
|
|
continue
|
|
|
|
other_name = other_desc.split(' ', 1)[0].strip('"')
|
|
if other_name == column:
|
|
relations[field_name] = (other_name, table)
|
|
break
|
|
|
|
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 = []
|
|
|
|
# Schema for this table
|
|
cursor.execute("SELECT sql FROM sqlite_master WHERE tbl_name = %s AND type = %s", [table_name, "table"])
|
|
results = cursor.fetchone()[0].strip()
|
|
results = results[results.index('(') + 1:results.rindex(')')]
|
|
|
|
# Walk through and look for references to other tables. SQLite doesn't
|
|
# really have enforced references, but since it echoes out the SQL used
|
|
# to create the table we can look for REFERENCES statements used there.
|
|
for field_index, field_desc in enumerate(results.split(',')):
|
|
field_desc = field_desc.strip()
|
|
if field_desc.startswith("UNIQUE"):
|
|
continue
|
|
|
|
m = re.search('"(.*)".*references (.*) \(["|](.*)["|]\)', field_desc, re.I)
|
|
if not m:
|
|
continue
|
|
|
|
# This will append (column_name, referenced_table_name, referenced_column_name) to key_columns
|
|
key_columns.append(tuple(s.strip('"') for s in m.groups()))
|
|
|
|
return key_columns
|
|
|
|
def get_indexes(self, cursor, table_name):
|
|
indexes = {}
|
|
for info in self._table_info(cursor, table_name):
|
|
if info['pk'] != 0:
|
|
indexes[info['name']] = {'primary_key': True,
|
|
'unique': False}
|
|
cursor.execute('PRAGMA index_list(%s)' % self.connection.ops.quote_name(table_name))
|
|
# seq, name, unique
|
|
for index, unique in [(field[1], field[2]) for field in cursor.fetchall()]:
|
|
cursor.execute('PRAGMA index_info(%s)' % self.connection.ops.quote_name(index))
|
|
info = cursor.fetchall()
|
|
# Skip indexes across multiple fields
|
|
if len(info) != 1:
|
|
continue
|
|
name = info[0][2] # seqno, cid, name
|
|
indexes[name] = {'primary_key': indexes.get(name, {}).get("primary_key", False),
|
|
'unique': unique}
|
|
return indexes
|
|
|
|
def get_primary_key_column(self, cursor, table_name):
|
|
"""
|
|
Get the column name of the primary key for the given table.
|
|
"""
|
|
# Don't use PRAGMA because that causes issues with some transactions
|
|
cursor.execute("SELECT sql FROM sqlite_master WHERE tbl_name = %s AND type = %s", [table_name, "table"])
|
|
row = cursor.fetchone()
|
|
if row is None:
|
|
raise ValueError("Table %s does not exist" % table_name)
|
|
results = row[0].strip()
|
|
results = results[results.index('(') + 1:results.rindex(')')]
|
|
for field_desc in results.split(','):
|
|
field_desc = field_desc.strip()
|
|
m = re.search('"(.*)".*PRIMARY KEY( AUTOINCREMENT)?$', field_desc)
|
|
if m:
|
|
return m.groups()[0]
|
|
return None
|
|
|
|
def _table_info(self, cursor, name):
|
|
cursor.execute('PRAGMA table_info(%s)' % self.connection.ops.quote_name(name))
|
|
# cid, name, type, notnull, default_value, pk
|
|
return [{
|
|
'name': field[1],
|
|
'type': field[2],
|
|
'size': get_field_size(field[2]),
|
|
'null_ok': not field[3],
|
|
'default': field[4],
|
|
'pk': field[5], # undocumented
|
|
} for field in cursor.fetchall()]
|
|
|
|
def get_constraints(self, cursor, table_name):
|
|
"""
|
|
Retrieves any constraints or keys (unique, pk, fk, check, index) across one or more columns.
|
|
"""
|
|
constraints = {}
|
|
# Get the index info
|
|
cursor.execute("PRAGMA index_list(%s)" % self.connection.ops.quote_name(table_name))
|
|
for row in cursor.fetchall():
|
|
# Sqlite3 3.8.9+ has 5 columns, however older versions only give 3
|
|
# columns. Discard last 2 columns if there.
|
|
number, index, unique = row[:3]
|
|
# Get the index info for that index
|
|
cursor.execute('PRAGMA index_info(%s)' % self.connection.ops.quote_name(index))
|
|
for index_rank, column_rank, column in cursor.fetchall():
|
|
if index not in constraints:
|
|
constraints[index] = {
|
|
"columns": [],
|
|
"primary_key": False,
|
|
"unique": bool(unique),
|
|
"foreign_key": False,
|
|
"check": False,
|
|
"index": True,
|
|
}
|
|
constraints[index]['columns'].append(column)
|
|
# Get the PK
|
|
pk_column = self.get_primary_key_column(cursor, table_name)
|
|
if pk_column:
|
|
# SQLite doesn't actually give a name to the PK constraint,
|
|
# so we invent one. This is fine, as the SQLite backend never
|
|
# deletes PK constraints by name, as you can't delete constraints
|
|
# in SQLite; we remake the table with a new PK instead.
|
|
constraints["__primary__"] = {
|
|
"columns": [pk_column],
|
|
"primary_key": True,
|
|
"unique": False, # It's not actually a unique constraint.
|
|
"foreign_key": False,
|
|
"check": False,
|
|
"index": False,
|
|
}
|
|
return constraints
|