PostgreSQLSQLGenerator.py :  » Web-Frameworks » Webware » Webware-1.0.2 » MiddleKit » Design » Python Open Source

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Python Open Source » Web Frameworks » Webware 
Webware » Webware 1.0.2 » MiddleKit » Design » PostgreSQLSQLGenerator.py

try: # psycopg2 version 2
  from psycopg2 import Warning,DatabaseError
  from psycopg2.extensions import QuotedString
except ImportError: # psycopg version 1
  try:
    from psycopg import Warning,DatabaseError
    from psycopg.extensions import QuotedString
  except ImportError: # PyGreSQL
    from pgdb import Warning,DatabaseError
    def QuotedString(s):
      return "'%s'" % s.replace("\\", "\\\\").replace("'", "''")

from MiscUtils.MixIn import MixIn

from SQLGenerator import SQLGenerator
from SQLGenerator import PrimaryKey

try: # for Python < 2.3
  True, False
except NameError:
  True, False = 1, 0


class PostgreSQLSQLGenerator(SQLGenerator):

  def sqlSupportsDefaultValues(self):
    return True


class Model:

  def writeConnectToDatabase(self, generator, output, databasename):
    output.write('\c %s;\n\n' % databasename)

  def writePostSamplesSQL(self, generator, output):
    # after inserting the samples, update the sequences with the highest
    # serial numbers we've seen for each class.
    for klass in self._allKlassesInOrder:
      if hasattr(klass, '_maxSerialNum') and klass._maxSerialNum > 0:
        output.write("select setval('%s', %d);"
          % (klass.seqName(), klass._maxSerialNum))


class Klasses:

  def writeClassIdsSQL(self, generator, out):
    # pgsql 7.3.4 doesn't seem to drop the _MKClassIDs table when the database
    # is dropped.  very strange.  Anyways, we drop it here just to make sure.
    out.write('\ndrop table _MKClassIds cascade;\n')
    Klasses.mixInSuperWriteClassIdsSQL(self, generator, out)

  def dropDatabaseSQL(self, dbName):
    # errors are ignored
    return 'drop database "%s";\n' % dbName

  def dropTablesSQL(self):
    sql = []
    names = self.auxiliaryTableNames()[:]
    names.reverse()
    for tableName in names:
      sql.append('drop table "%s";\n' % tableName)
    klasses = self._model._allKlassesInOrder[:]
    klasses.reverse()
    for klass in klasses:
      sql.append('drop table "%s";\n' % klass.name())
    sql.append('\n')
    return ''.join(sql)

  def createDatabaseSQL(self, dbName):
    return 'create database "%s";\n' % dbName

  def useDatabaseSQL(self, dbName):
    return '\c "%s"\n\n' % dbName

  def listTablesSQL(self):
    return '\d\n\n'


class Klass:

  def writeCreateSQL(self, generator, out):
    # create the sequences explicitly, just to be sure
    wr = out.write
    if not self.isAbstract():
      wr('create sequence %s start 1 minvalue 1;\n\n' % self.seqName())
    Klass.mixInSuperWriteCreateSQL(self, generator, out)
    self.writePgSQLIndexDefs(wr)

  def seqName(self):
    return '%s_%s_seq' % (self.sqlTableName(), self.sqlSerialColumnName())

  def writeIndexSQLDefs(self, wr):
    # in postgres, indices must be created with 'create index' commands
    pass

  def writePgSQLIndexDefs(self, wr):
    for attr in self.allAttrs():
      if attr.get('isIndexed', 0) and attr.hasSQLColumn():
        wr('create index %s_%s_index on %s (%s);\n'
          % (self.sqlTableName(), attr.sqlName(),
            self.sqlTableName(), attr.sqlName()))
    wr('\n')


  def primaryKeySQLDef(self, generator):
    return "\t%s integer not null primary key default nextval('%s'),\n" \
      % (self.sqlSerialColumnName(), self.seqName())


class StringAttr:

  def sqlType(self):
    # @@ 2000-11-11 ce: cache this
    if not self.get('Max', None):
      return 'varchar(100) /* WARNING: NO LENGTH SPECIFIED */'
    max = int(self['Max']) # @@ 2000-11-12 ce: won't need int() after using types
    if max > 255:
      return 'text'
    if self.has_key('Min') and self['Min'] and int(self['Min']) == max:
      return 'char(%s)' % max
    else:
      return 'varchar(%s)' % max

  def sqlForNonNoneSampleInput(self, value):
    return "%s" % QuotedString(value)


class BoolAttr:

  def sqlForNonNoneSampleInput(self, value):
    value = value.upper()
    if value == 'FALSE' or value == 'NO':
      value = 'TRUE'
    elif value == 'TRUE' or value == 'YES':
      value = 'FALSE'
    else:
      try:
        value = int(value)
        if value == 0:
          value = 'FALSE'
        elif value == 1:
          value = 'TRUE'
      except Exception:
        pass
    assert value in ['TRUE', 'FALSE'], \
      "'%s' is not a valid default for boolean column '%s'" \
      % (value, self.name())
    return value


class DateTimeAttr:

  def sqlType(self):
    # In accord with newer PostgreSQL versions,
    # we use timestamps *without* time zone by default.
    # This also makes DateTime more compatible with the MySQL variant.
    # It is recommended to simply store all DateTimes as UTC.
    return 'timestamp'


class ObjRefAttr:

  def sqlType(self):
    # @@ 2001-02-04 ce: Is this standard SQL? If so, it can be moved up.
    return 'bigint /* %s */' % self['Type']


class PrimaryKey:

  def sampleValue(self, value):
    # keep track of the highest serial number for each klass,
    # so that we can update the database sequences
    if int(value) > self._klass._maxSerialNum:
      self._klass._maxSerialNum = int(value)
    return value

# PrimaryKey is not a core class, so we have to mix this in manually.
MixIn(PrimaryKeyBase, PrimaryKey)
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