Ticket #7384: introspection.py

File introspection.py, 3.9 KB (added by Marc Mengel <mengel@…>, 16 years ago)
Line 
1
2import re
3
4foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)")
5
6from cx_Oracle import NUMBER, ROWID, LONG_STRING, STRING, FIXED_CHAR, Timestamp, LOB, BLOB, CLOB, BINARY
7
8
9def get_table_list(cursor):
10 "Returns a list of table names in the current database."
11 cursor.execute("SELECT TABLE_NAME FROM USER_TABLES")
12 return [row[0] for row in cursor.fetchall()]
13
14table_description_cache = {}
15
16def get_table_description(cursor, table_name):
17 "Returns a description of the table, with the DB-API cursor.description interface."
18 cursor.execute("SELECT * FROM \"%s\" where rownum < 2" % table_name)
19 return cursor.description
20
21_name_to_index_cache = {}
22
23def _name_to_index(cursor, table_name):
24 """
25 Returns a dictionary of {field_name: field_index} for the given table.
26 Indexes are 0-based.
27 """
28 if not _name_to_index_cache.get(table_name):
29 _name_to_index_cache[table_name] = dict([(d[0], i) for i, d in enumerate(get_table_description(cursor, table_name))])
30 return _name_to_index_cache[table_name]
31
32
33def columnum(cursor, table_name, column_name):
34 res = _name_to_index(cursor,table_name)[column_name]
35 return res
36
37def get_relations(cursor, table_name):
38 """
39 Returns a dictionary of {field_index: (field_index_other_table, other_table)}
40 representing all relationships to the given table. Indexes are 0-based.
41
42 """
43
44 cursor.execute("select col.column_name, con.constraint_type from all_cons_columns col, all_constraints con where col.constraint_name = con.constraint_name and con.constraint_type = 'P' and col.table_name = '%s'" % table_name )
45 rows = cursor.fetchall()
46 try:
47 primary_key = rows[0][0];
48 except:
49 primary_key = None
50
51 print "Got primary key: ", primary_key
52
53 res = {}
54 query = """
55 select col.column_name, col.table_name, col.constraint_name,
56 c2.table_name, c2.column_name
57 from all_cons_columns col, all_constraints con, all_cons_columns c2
58 where con.constraint_type = 'R'
59 and con.r_constraint_name = c2.constraint_name
60 and con.constraint_name = col.constraint_name
61 and not (col.position = c2.position and
62 col.table_name = c2.table_name)
63 and col.table_name = '%s'
64 """
65 cursor.execute(query % table_name)
66 relations = {}
67 rows = cursor.fetchall()
68 for row in rows:
69 print "relation: %s -> %s(%s)" % (row[0], row[3], row[4])
70 if row[0] != primary_key:
71 try:
72 relations[columnum(cursor, table_name, row[0])] = (
73 columnum(cursor,row[3],row[4]),
74 row[3]
75 )
76 except:
77 pass
78 return relations
79
80def get_indexes(cursor, table_name):
81 """
82 Returns a dictionary of fieldname -> infodict for the given table,
83 where each infodict is in the format:
84 {'primary_key': boolean representing whether it's the primary key,
85 'unique': boolean representing whether it's a unique index}
86 """
87 cursor.execute("select col.column_name, con.constraint_type from all_cons_columns col, all_constraints con where col.constraint_name = con.constraint_name and con.constraint_type in ('P','U') and col.table_name = '%s'" % table_name )
88 rows = cursor.fetchall()
89 res = {}
90 for r in rows:
91 res[r[0]] = {'primary_key': 0, 'unique': 0}
92
93 for r in rows:
94 if r[1] == 'P':
95 res[r[0]]['primary_key'] = 1
96 if r[1] == 'U':
97 res[r[0]]['unique'] = 1
98
99 return res
100
101# Maps type codes to Django Field types.
102DATA_TYPES_REVERSE = {
103 NUMBER: 'IntegerField',
104 ROWID: 'IntegerField',
105 LONG_STRING: 'TextField',
106 STRING: 'TextField',
107 FIXED_CHAR: 'CharField',
108 Timestamp: 'DateTimeField',
109 LOB: 'TextField',
110 BLOB: 'TextField',
111 CLOB: 'TextField',
112 BINARY:'TextField',
113}
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