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
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
|
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along with
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
"""Help to generate SQL string usable by the Python DB-API
:author: Logilab
:copyright: 2003-2008 LOGILAB S.A. (Paris, FRANCE)
:contact: http://www.logilab.fr/ -- mailto:python-projects@logilab.org
"""
__docformat__ = "restructuredtext en"
# SQLGenerator ################################################################
class SQLGenerator :
"""
Helper class to generate SQL strings to use with python's DB-API
"""
def where(self, keys, addon=None) :
"""
keys : list of keys
>>> s = SQLGenerator()
>>> s.where(['nom'])
'nom = %(nom)s'
>>> s.where(['nom','prenom'])
'nom = %(nom)s AND prenom = %(prenom)s'
>>> s.where(['nom','prenom'], 'x.id = y.id')
'x.id = y.id AND nom = %(nom)s AND prenom = %(prenom)s'
"""
restriction = ["%s = %%(%s)s" % (x, x) for x in keys]
if addon:
restriction.insert(0, addon)
return " AND ".join(restriction)
def set(self, keys) :
"""
keys : list of keys
>>> s = SQLGenerator()
>>> s.set(['nom'])
'nom = %(nom)s'
>>> s.set(['nom','prenom'])
'nom = %(nom)s, prenom = %(prenom)s'
"""
return ", ".join(["%s = %%(%s)s" % (x, x) for x in keys])
def insert(self, table, params) :
"""
table : name of the table
params : dictionnary that will be used as in cursor.execute(sql,params)
>>> s = SQLGenerator()
>>> s.insert('test',{'nom':'dupont'})
'INSERT INTO test ( nom ) VALUES ( %(nom)s )'
>>> s.insert('test',{'nom':'dupont','prenom':'jean'})
'INSERT INTO test ( nom, prenom ) VALUES ( %(nom)s, %(prenom)s )'
"""
keys = ', '.join(params.keys())
values = ', '.join(["%%(%s)s" % x for x in params])
sql = 'INSERT INTO %s ( %s ) VALUES ( %s )' % (table, keys, values)
return sql
def select(self, table, params) :
"""
table : name of the table
params : dictionnary that will be used as in cursor.execute(sql,params)
>>> s = SQLGenerator()
>>> s.select('test',{})
'SELECT * FROM test'
>>> s.select('test',{'nom':'dupont'})
'SELECT * FROM test WHERE nom = %(nom)s'
>>> s.select('test',{'nom':'dupont','prenom':'jean'})
'SELECT * FROM test WHERE nom = %(nom)s AND prenom = %(prenom)s'
"""
sql = 'SELECT * FROM %s' % table
where = self.where(params.keys())
if where :
sql = sql + ' WHERE %s' % where
return sql
def adv_select(self, model, tables, params, joins=None) :
"""
model : list of columns to select
tables : list of tables used in from
params : dictionnary that will be used as in cursor.execute(sql, params)
joins : optional list of restriction statements to insert in the where
clause. Usually used to perform joins.
>>> s = SQLGenerator()
>>> s.adv_select(['column'],[('test', 't')], {})
'SELECT column FROM test AS t'
>>> s.adv_select(['column'],[('test', 't')], {'nom':'dupont'})
'SELECT column FROM test AS t WHERE nom = %(nom)s'
"""
table_names = ["%s AS %s" % (k, v) for k, v in tables]
sql = 'SELECT %s FROM %s' % (', '.join(model), ', '.join(table_names))
if joins and type(joins) != type(''):
joins = ' AND '.join(joins)
where = self.where(params.keys(), joins)
if where :
sql = sql + ' WHERE %s' % where
return sql
def delete(self, table, params) :
"""
table : name of the table
params : dictionnary that will be used as in cursor.execute(sql,params)
>>> s = SQLGenerator()
>>> s.delete('test',{'nom':'dupont'})
'DELETE FROM test WHERE nom = %(nom)s'
>>> s.delete('test',{'nom':'dupont','prenom':'jean'})
'DELETE FROM test WHERE nom = %(nom)s AND prenom = %(prenom)s'
"""
where = self.where(params.keys())
sql = 'DELETE FROM %s WHERE %s' % (table, where)
return sql
def update(self, table, params, unique) :
"""
table : name of the table
params : dictionnary that will be used as in cursor.execute(sql,params)
>>> s = SQLGenerator()
>>> s.update('test', {'id':'001','nom':'dupont'}, ['id'])
'UPDATE test SET nom = %(nom)s WHERE id = %(id)s'
>>> s.update('test',{'id':'001','nom':'dupont','prenom':'jean'},['id'])
'UPDATE test SET nom = %(nom)s, prenom = %(prenom)s WHERE id = %(id)s'
"""
where = self.where(unique)
set = self.set([key for key in params if key not in unique])
sql = 'UPDATE %s SET %s WHERE %s' % (table, set, where)
return sql
class BaseTable:
"""
Another helper class to ease SQL table manipulation
"""
# table_name = "default"
# supported types are s/i/d
# table_fields = ( ('first_field','s'), )
# primary_key = 'first_field'
def __init__(self, table_name, table_fields, primary_key=None):
if primary_key is None:
self._primary_key = table_fields[0][0]
else:
self._primary_key = primary_key
self._table_fields = table_fields
self._table_name = table_name
info = {
'key' : self._primary_key,
'table' : self._table_name,
'columns' : ",".join( [ f for f,t in self._table_fields ] ),
'values' : ",".join( [sql_repr(t, "%%(%s)s" % f)
for f,t in self._table_fields] ),
'updates' : ",".join( ["%s=%s" % (f, sql_repr(t, "%%(%s)s" % f))
for f,t in self._table_fields] ),
}
self._insert_stmt = ("INSERT into %(table)s (%(columns)s) "
"VALUES (%(values)s) WHERE %(key)s=%%(key)s") % info
self._update_stmt = ("UPDATE %(table)s SET (%(updates)s) "
"VALUES WHERE %(key)s=%%(key)s") % info
self._select_stmt = ("SELECT %(columns)s FROM %(table)s "
"WHERE %(key)s=%%(key)s") % info
self._delete_stmt = ("DELETE FROM %(table)s "
"WHERE %(key)s=%%(key)s") % info
for k, t in table_fields:
if hasattr(self, k):
raise ValueError("Cannot use %s as a table field" % k)
setattr(self, k,None)
def as_dict(self):
d = {}
for k, t in self._table_fields:
d[k] = getattr(self, k)
return d
def select(self, cursor):
d = { 'key' : getattr(self,self._primary_key) }
cursor.execute(self._select_stmt % d)
rows = cursor.fetchall()
if len(rows)!=1:
msg = "Select: ambiguous query returned %d rows"
raise ValueError(msg % len(rows))
for (f, t), v in zip(self._table_fields, rows[0]):
setattr(self, f, v)
def update(self, cursor):
d = self.as_dict()
cursor.execute(self._update_stmt % d)
def delete(self, cursor):
d = { 'key' : getattr(self,self._primary_key) }
# Helper functions #############################################################
def name_fields(cursor, records) :
"""
Take a cursor and a list of records fetched with that cursor, then return a
list of dictionnaries (one for each record) whose keys are column names and
values are records' values.
cursor : cursor used to execute the query
records : list returned by fetch*()
"""
result = []
for record in records :
record_dict = {}
for i in range(len(record)) :
record_dict[cursor.description[i][0]] = record[i]
result.append(record_dict)
return result
def sql_repr(type, val):
if type == 's':
return "'%s'" % (val,)
else:
return val
if __name__ == "__main__":
import doctest
from logilab.common import sqlgen
print doctest.testmod(sqlgen)
|
