1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
import re
from django.db.backends import BaseDatabaseIntrospection
# 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',
'date': 'DateField',
'datetime': 'DateTimeField',
'time': 'TimeField',
}
def __getitem__(self, key):
key = key.lower()
try:
return self.base_data_types_reverse[key]
except KeyError:
import re
m = re.search(r'^\s*(?:var)?char\s*\(\s*(\d+)\s*\)\s*$', key)
if m:
return ('CharField', {'max_length': int(m.group(1))})
raise KeyError
class DatabaseIntrospection(BaseDatabaseIntrospection):
data_types_reverse = FlexibleFieldLookupDict()
def get_table_list(self, cursor):
"Returns a list of table names in the current database."
# Skip the sqlite_sequence system table used for autoincrement key
# generation.
cursor.execute("""
SELECT name FROM sqlite_master
WHERE type='table' AND NOT name='sqlite_sequence'
ORDER BY name""")
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."
return [(info['name'], info['type'], None, None, None, None,
info['null_ok']) for info in self._table_info(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.
"""
# 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"])
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
table, column = [s.strip('"') for s in m.groups()]
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_index, other_desc in enumerate(other_table_results.split(',')):
other_desc = other_desc.strip()
if other_desc.startswith('UNIQUE'):
continue
name = other_desc.split(' ', 1)[0].strip('"')
if name == column:
relations[field_index] = (other_index, 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):
"""
Returns a dictionary of fieldname -> infodict for the given table,
where each infodict is in the format:
{'primary_key': boolean representing whether it's the primary key,
'unique': boolean representing whether it's a unique index}
"""
indexes = {}
for info in self._table_info(cursor, table_name):
indexes[info['name']] = {'primary_key': info['pk'] != 0,
'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()]:
if not unique:
continue
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]['unique'] = True
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"])
results = cursor.fetchone()[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$', 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, dflt_value, pk
return [{'name': field[1],
'type': field[2],
'null_ok': not field[3],
'pk': field[5] # undocumented
} for field in cursor.fetchall()]
|
