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1 from django.db.backends.mysql.base import DatabaseOperations |
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2 from MySQLdb import ProgrammingError, OperationalError |
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3 from MySQLdb.constants import FIELD_TYPE |
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4 import re |
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5 |
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6 quote_name = DatabaseOperations().quote_name |
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7 foreign_key_re = re.compile(r"\sCONSTRAINT `[^`]*` FOREIGN KEY \(`([^`]*)`\) REFERENCES `([^`]*)` \(`([^`]*)`\)") |
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8 |
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9 def get_table_list(cursor): |
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10 "Returns a list of table names in the current database." |
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11 cursor.execute("SHOW TABLES") |
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12 return [row[0] for row in cursor.fetchall()] |
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13 |
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14 def get_table_description(cursor, table_name): |
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15 "Returns a description of the table, with the DB-API cursor.description interface." |
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16 cursor.execute("SELECT * FROM %s LIMIT 1" % quote_name(table_name)) |
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17 return cursor.description |
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18 |
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19 def _name_to_index(cursor, table_name): |
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20 """ |
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21 Returns a dictionary of {field_name: field_index} for the given table. |
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22 Indexes are 0-based. |
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23 """ |
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24 return dict([(d[0], i) for i, d in enumerate(get_table_description(cursor, table_name))]) |
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25 |
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26 def get_relations(cursor, table_name): |
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27 """ |
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28 Returns a dictionary of {field_index: (field_index_other_table, other_table)} |
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29 representing all relationships to the given table. Indexes are 0-based. |
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30 """ |
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31 my_field_dict = _name_to_index(cursor, table_name) |
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32 constraints = [] |
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33 relations = {} |
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34 try: |
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35 # This should work for MySQL 5.0. |
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36 cursor.execute(""" |
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37 SELECT column_name, referenced_table_name, referenced_column_name |
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38 FROM information_schema.key_column_usage |
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39 WHERE table_name = %s |
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40 AND table_schema = DATABASE() |
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41 AND referenced_table_name IS NOT NULL |
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42 AND referenced_column_name IS NOT NULL""", [table_name]) |
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43 constraints.extend(cursor.fetchall()) |
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44 except (ProgrammingError, OperationalError): |
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45 # Fall back to "SHOW CREATE TABLE", for previous MySQL versions. |
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46 # Go through all constraints and save the equal matches. |
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47 cursor.execute("SHOW CREATE TABLE %s" % quote_name(table_name)) |
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48 for row in cursor.fetchall(): |
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49 pos = 0 |
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50 while True: |
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51 match = foreign_key_re.search(row[1], pos) |
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52 if match == None: |
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53 break |
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54 pos = match.end() |
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55 constraints.append(match.groups()) |
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56 |
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57 for my_fieldname, other_table, other_field in constraints: |
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58 other_field_index = _name_to_index(cursor, other_table)[other_field] |
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59 my_field_index = my_field_dict[my_fieldname] |
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60 relations[my_field_index] = (other_field_index, other_table) |
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61 |
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62 return relations |
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63 |
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64 def get_indexes(cursor, table_name): |
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65 """ |
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66 Returns a dictionary of fieldname -> infodict for the given table, |
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67 where each infodict is in the format: |
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68 {'primary_key': boolean representing whether it's the primary key, |
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69 'unique': boolean representing whether it's a unique index} |
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70 """ |
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71 cursor.execute("SHOW INDEX FROM %s" % quote_name(table_name)) |
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72 indexes = {} |
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73 for row in cursor.fetchall(): |
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74 indexes[row[4]] = {'primary_key': (row[2] == 'PRIMARY'), 'unique': not bool(row[1])} |
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75 return indexes |
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76 |
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77 DATA_TYPES_REVERSE = { |
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78 FIELD_TYPE.BLOB: 'TextField', |
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79 FIELD_TYPE.CHAR: 'CharField', |
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80 FIELD_TYPE.DECIMAL: 'DecimalField', |
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81 FIELD_TYPE.DATE: 'DateField', |
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82 FIELD_TYPE.DATETIME: 'DateTimeField', |
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83 FIELD_TYPE.DOUBLE: 'FloatField', |
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84 FIELD_TYPE.FLOAT: 'FloatField', |
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85 FIELD_TYPE.INT24: 'IntegerField', |
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86 FIELD_TYPE.LONG: 'IntegerField', |
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87 FIELD_TYPE.LONGLONG: 'IntegerField', |
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88 FIELD_TYPE.SHORT: 'IntegerField', |
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89 FIELD_TYPE.STRING: 'CharField', |
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90 FIELD_TYPE.TIMESTAMP: 'DateTimeField', |
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91 FIELD_TYPE.TINY: 'IntegerField', |
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92 FIELD_TYPE.TINY_BLOB: 'TextField', |
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93 FIELD_TYPE.MEDIUM_BLOB: 'TextField', |
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94 FIELD_TYPE.LONG_BLOB: 'TextField', |
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95 FIELD_TYPE.VAR_STRING: 'CharField', |
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96 } |