0001from itertools import count
0002from types import *
0003from converters import sqlrepr
0004
0005creationOrder = count()
0006
0007class SODatabaseIndex(object):
0008
0009 def __init__(self,
0010 soClass,
0011 name,
0012 columns,
0013 creationOrder,
0014 unique=False):
0015 self.soClass = soClass
0016 self.name = name
0017 self.descriptions = self.convertColumns(columns)
0018 self.creationOrder = creationOrder
0019 self.unique = unique
0020
0021 def get(self, *args, **kw):
0022 if not self.unique:
0023 raise AttributeError, (
0024 "'%s' object has no attribute 'get' (index is not unique)" % self.name)
0025 connection = kw.pop('connection', None)
0026 if args and kw:
0027 raise TypeError, "You cannot mix named and unnamed arguments"
0028 columns = [d['column'] for d in self.descriptions
0029 if 'column' in d]
0030 if kw and len(kw) != len(columns) or args and len(args) != len(columns):
0031 raise TypeError, ("get() takes exactly %d argument and an optional "
0032 "named argument 'connection' (%d given)" % (
0033 len(columns), len(args)+len(kw)))
0034 if args:
0035 kw = {}
0036 for i in range(len(args)):
0037 if columns[i].foreignName is not None:
0038 kw[columns[i].foreignName] = args[i]
0039 else:
0040 kw[columns[i].name] = args[i]
0041 return self.soClass.selectBy(connection=connection, **kw).getOne()
0042
0043 def convertColumns(self, columns):
0044 """
0045 Converts all the columns to dictionary descriptors;
0046 dereferences string column names.
0047 """
0048 new = []
0049 for desc in columns:
0050 if not isinstance(desc, dict):
0051 desc = {'column': desc}
0052 if 'expression' in desc:
0053 assert 'column' not in desc, (
0054 'You cannot provide both an expression and a column '
0055 '(for %s in index %s in %s)' %
0056 (desc, self.name, self.soClass))
0057 assert 'length' not in desc, (
0058 'length does not apply to expressions (for %s in '
0059 'index %s in %s)' %
0060 (desc, self.name, self.soClass))
0061 new.append(desc)
0062 continue
0063 columnName = desc['column']
0064 if not isinstance(columnName, str):
0065 columnName = columnName.name
0066 colDict = self.soClass.sqlmeta.columns
0067 if columnName not in colDict:
0068 for possible in colDict.values():
0069 if possible.origName == columnName:
0070 column = possible
0071 break
0072 else:
0073
0074 raise ValueError, "The column by the name %r was not found in the class %r" % (columnName, self.soClass)
0075 else:
0076 column = colDict[columnName]
0077 desc['column'] = column
0078 new.append(desc)
0079 return new
0080
0081 def getExpression(self, desc, db):
0082 if isinstance(desc['expression'], str):
0083 return desc['expression']
0084 else:
0085 return sqlrepr(desc['expression'], db)
0086
0087 def sqliteCreateIndexSQL(self, soClass):
0088 if self.unique:
0089 uniqueOrIndex = 'UNIQUE INDEX'
0090 else:
0091 uniqueOrIndex = 'INDEX'
0092 spec = []
0093 for desc in self.descriptions:
0094 if 'expression' in desc:
0095 spec.append(self.getExpression(desc, 'sqlite'))
0096 else:
0097 spec.append(desc['column'].dbName)
0098 ret = 'CREATE %s %s_%s ON %s (%s)' % (uniqueOrIndex,
0100 self.soClass.sqlmeta.table,
0101 self.name,
0102 self.soClass.sqlmeta.table,
0103 ', '.join(spec))
0104 return ret
0105
0106 postgresCreateIndexSQL = maxdbCreateIndexSQL = mssqlCreateIndexSQL = sybaseCreateIndexSQL = firebirdCreateIndexSQL = sqliteCreateIndexSQL
0107 def mysqlCreateIndexSQL(self, soClass):
0108 if self.unique:
0109 uniqueOrIndex = 'UNIQUE'
0110 else:
0111 uniqueOrIndex = 'INDEX'
0112 spec = []
0113 for desc in self.descriptions:
0114 if 'expression' in desc:
0115 spec.append(self.getExpression(desc, 'mysql'))
0116 elif 'length' in desc:
0117 spec.append('%s(%d)' % (desc['column'].dbName, desc['length']))
0118 else:
0119 spec.append(desc['column'].dbName)
0120
0121 return 'ALTER TABLE %s ADD %s %s (%s)' % (soClass.sqlmeta.table, uniqueOrIndex,
0123 self.name,
0124 ', '.join(spec))
0125
0126
0127class DatabaseIndex(object):
0128 """
0129 This takes a variable number of parameters, each of which is a
0130 column for indexing. Each column may be a column object or the
0131 string name of the column (*not* the database name). You may also
0132 use dictionaries, to further customize the indexing of the column.
0133 The dictionary may have certain keys:
0134
0135 'column':
0136 The column object or string identifier.
0137 'length':
0138 MySQL will only index the first N characters if this is
0139 given. For other databases this is ignored.
0140 'expression':
0141 You can create an index based on an expression, e.g.,
0142 'lower(column)'. This can either be a string or a sqlbuilder
0143 expression.
0144
0145 Further keys may be added to the column specs in the future.
0146
0147 The class also take the keyword argument `unique`; if true then
0148 a UNIQUE index is created.
0149 """
0150
0151 baseClass = SODatabaseIndex
0152
0153 def __init__(self, *columns, **kw):
0154 kw['columns'] = columns
0155 self.kw = kw
0156 self.creationOrder = creationOrder.next()
0157
0158 def setName(self, value):
0159 assert self.kw.get('name') is None, "You cannot change a name after it has already been set (from %s to %s)" % (self.kw['name'], value)
0160 self.kw['name'] = value
0161
0162 def _get_name(self):
0163 return self.kw['name']
0164
0165 def _set_name(self, value):
0166 self.setName(value)
0167
0168 name = property(_get_name, _set_name)
0169
0170 def withClass(self, soClass):
0171 return self.baseClass(soClass=soClass,
0172 creationOrder=self.creationOrder, **self.kw)
0173
0174 def __repr__(self):
0175 return '<%s %s %s>' % (
0176 self.__class__.__name__,
0177 hex(abs(id(self)))[2:],
0178 self.kw)
0179
0180__all__ = ['DatabaseIndex']