/[thuban]/branches/WIP-pyshapelib-bramz/Thuban/Model/postgisdb.py
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revision 2059 by bh, Wed Feb 11 09:05:40 2004 UTC revision 2102 by bh, Thu Mar 11 21:04:30 2004 UTC
# Line 32  def psycopg_version(): Line 32  def psycopg_version():
32      return psycopg.__version__      return psycopg.__version__
33    
34  if psycopg is not None:  if psycopg is not None:
35        # type_map maps psycopg type objects.  It's a list of pairs since
36        # the psycopg type objects are unhashable.
37      type_map = [(psycopg.STRING, table.FIELDTYPE_STRING),      type_map = [(psycopg.STRING, table.FIELDTYPE_STRING),
38                  (psycopg.INTEGER, table.FIELDTYPE_INT),                  (psycopg.INTEGER, table.FIELDTYPE_INT),
39                    (psycopg.ROWID, table.FIELDTYPE_INT),
40                  (psycopg.FLOAT, table.FIELDTYPE_DOUBLE)]                  (psycopg.FLOAT, table.FIELDTYPE_DOUBLE)]
41    
42        # _raw_type_map maps the postgresql type constants to Thuban type
43        # constants.  This is very low level and postgresql specific and
44        # should be used only when necessary.
45        _raw_type_map = {}
46        def _fill_raw_type_map():
47            for psycopg_type, thuban_type in type_map:
48                for value in psycopg_type.values:
49                    _raw_type_map[value] = thuban_type
50        _fill_raw_type_map()
51    
52    
53  def quote_identifier(ident):  def quote_identifier(ident):
54      """Return a quoted version of the identifier ident.      """Return a quoted version of the identifier ident.
# Line 135  class PostGISConnection: Line 148  class PostGISConnection:
148    
149      def GeometryTables(self):      def GeometryTables(self):
150          """Return a list with the names of all tables with a geometry column"""          """Return a list with the names of all tables with a geometry column"""
151    
152            # The query is basically taken from the psql v. 7.2.1.  When
153            # started with -E it prints the queries used for internal
154            # commands such as \d, which does mostly what we need here.
155          cursor = self.connection.cursor()          cursor = self.connection.cursor()
156          cursor.execute("SELECT f_table_name FROM geometry_columns;")          cursor.execute("SELECT c.relname FROM pg_class c"
157                           " WHERE c.relkind IN ('r', 'v')"
158                                 # Omit the system tables
159                                 " AND c.relname !~ '^pg_'"
160                                 # Omit the special PostGIS tables
161                                 " AND c.relname NOT IN ('geometry_columns',"
162                                                       " 'spatial_ref_sys')"
163                                " AND %d in (SELECT a.atttypid FROM pg_attribute a"
164                                           " WHERE a.attrelid = c.oid)"
165                           " ORDER BY c.relname;", (self.geometry_type,))
166          result = [row[0] for row in cursor.fetchall()]          result = [row[0] for row in cursor.fetchall()]
167          self.connection.commit()          self.connection.commit()
168          return result          return result
169    
170        def table_columns(self, tablename):
171            """Experimental: return information about the columns of a table
172    
173            Return value is a list of (name, type) pairs where name is the
174            name of the column and type either one of the field type columns
175            or the string 'geometry' indicating a geometry column.
176    
177            The intended use of this method is for table selection dialogs
178            which need to determine which columns are usable as id or
179            geometry columns respectively.  Suitable id columns will have
180            type FIELDTYPE_INT and geometry columns will have 'geometry'.
181            """
182            result = []
183            cursor = self.connection.cursor()
184    
185            # This query is taken basically from the \d command of psql
186            # 7.2.1
187            cursor.execute("SELECT a.attname, a.atttypid, a.attnum"
188                           " FROM pg_class c, pg_attribute a"
189                                " WHERE c.relname = %s AND a.attrelid = c.oid"
190                           " ORDER BY a.attnum;", (tablename,))
191    
192            for row in cursor.fetchall():
193                col_name, col_type, col_attnum = row
194                col = None
195                if col_attnum < 1:
196                    # It's a system column.  Only the OID is interesting
197                    # here
198                    if col_name == "oid":
199                        col = (col_name, _raw_type_map[col_type])
200                else:
201                    # If it's an integer
202                    thuban_type = _raw_type_map.get(col_type)
203                    if thuban_type is not None:
204                        col = (col_name, thuban_type)
205                    elif row[1] == self.geometry_type:
206                        col = (col_name, "geometry")
207                if col is not None:
208                    result.append(col)
209    
210            return result
211    
212      def cursor(self):      def cursor(self):
213          """Return a DB API 2.0 cursor for the database"""          """Return a DB API 2.0 cursor for the database"""
214          return self.connection.cursor()          return self.connection.cursor()
# Line 175  class PostGISTable: Line 243  class PostGISTable:
243      descriptions returned by Columns() and other methods.      descriptions returned by Columns() and other methods.
244      """      """
245    
246      def __init__(self, db, tablename):      def __init__(self, db, tablename, id_column = None):
247          """Initialize the PostGISTable.          """Initialize the PostGISTable.
248    
249          The db parameter should be an instance of PostGISConnection and          The db parameter should be an instance of PostGISConnection and
250          tablename the name of a table in the database represented by db.          tablename the name of a table in the database represented by db.
251    
252            The id_column parameter should be the name of a column in the
253            table that can be used to identify rows.  The column must have
254            the type integer and be unique and not null.
255    
256            For backwards compatibility reasons, the id_column parameter is
257            optional.  If not given the table must have a column called
258            'gid' which is used as the id_column.  New code should always
259            provide this parameter.
260          """          """
261          self.db = db          self.db = db
262          self.tablename = tablename          self.tablename = tablename
263          # Tablename quoted for use in SQL statements.          # Tablename quoted for use in SQL statements.
264          self.quoted_tablename = quote_identifier(tablename)          self.quoted_tablename = quote_identifier(tablename)
265    
266            if not id_column:
267                id_column = "gid"
268            self.id_column = id_column
269            # id column name quoted for use in SQL statements.
270            self.quoted_id_column = quote_identifier(id_column)
271    
272          # Map column names and indices to column objects.          # Map column names and indices to column objects.
273          self.column_map = {}          self.column_map = {}
274    
# Line 236  class PostGISTable: Line 319  class PostGISTable:
319          """Return the dbconnection used by the table"""          """Return the dbconnection used by the table"""
320          return self.db          return self.db
321    
322        def IDColumn(self):
323            """Return the column description object for the id column.
324    
325            If the oid column was used as the id column, the return value is
326            not one of the regular column objects that would be returned by
327            e.g. the Column() method, but it still has meaningful name
328            attribute.
329            """
330            if self.id_column == "oid":
331                return PostGISColumn(self.id_column, table.FIELDTYPE_INT, None)
332            return self.column_map[self.id_column]
333    
334      def TableName(self):      def TableName(self):
335          """Return the name of the table in the database"""          """Return the name of the table in the database"""
336          return self.tablename          return self.tablename
# Line 272  class PostGISTable: Line 367  class PostGISTable:
367      def RowIdToOrdinal(self, gid):      def RowIdToOrdinal(self, gid):
368          """Return the row ordinal given its id"""          """Return the row ordinal given its id"""
369          cursor = self.db.cursor()          cursor = self.db.cursor()
370          cursor.execute("SELECT count(*) FROM %s WHERE gid < %d;"          cursor.execute("SELECT count(*) FROM %s WHERE %s < %d;"
371                         % (self.quoted_tablename, gid))                         % (self.quoted_tablename, self.quoted_id_column, gid))
372          return cursor.fetchone()[0]          return cursor.fetchone()[0]
373    
374      def RowOrdinalToId(self, num):      def RowOrdinalToId(self, num):
375          """Return the rowid for given its ordinal"""          """Return the rowid for given its ordinal"""
376          cursor = self.db.cursor()          cursor = self.db.cursor()
377          cursor.execute("SELECT gid FROM %s LIMIT 1 OFFSET %d;"          cursor.execute("SELECT %s FROM %s LIMIT 1 OFFSET %d;"
378                         % (self.quoted_tablename, num))                         % (self.quoted_id_column, self.quoted_tablename, num))
379          return cursor.fetchone()[0]          return cursor.fetchone()[0]
380    
381      def ReadRowAsDict(self, row, row_is_ordinal = 0):      def ReadRowAsDict(self, row, row_is_ordinal = 0):
# Line 288  class PostGISTable: Line 383  class PostGISTable:
383          if row_is_ordinal:          if row_is_ordinal:
384              stmt = self.query_stmt + " LIMIT 1 OFFSET %d" % row              stmt = self.query_stmt + " LIMIT 1 OFFSET %d" % row
385          else:          else:
386              stmt = self.query_stmt + " WHERE gid = %d" % row              stmt = self.query_stmt + " WHERE %s = %d" % (self.quoted_id_column,
387                                                             row)
388          cursor.execute(stmt)          cursor.execute(stmt)
389          result = {}          result = {}
390          for col, value in zip(self.columns, cursor.fetchone()):          for col, value in zip(self.columns, cursor.fetchone()):
# Line 302  class PostGISTable: Line 398  class PostGISTable:
398                      (self.column_map[col].quoted_name, self.quoted_tablename,                      (self.column_map[col].quoted_name, self.quoted_tablename,
399                       row))                       row))
400          else:          else:
401              stmt = ("SELECT %s FROM %s WHERE gid = %d" %              stmt = ("SELECT %s FROM %s WHERE %s = %d" %
402                      (self.column_map[col].quoted_name, self.quoted_tablename,                      (self.column_map[col].quoted_name, self.quoted_tablename,
403                       row))                       self.quoted_id_column, row))
404          cursor.execute(stmt)          cursor.execute(stmt)
405          return cursor.fetchone()[0]          return cursor.fetchone()[0]
406    
# Line 336  class PostGISTable: Line 432  class PostGISTable:
432              right_template = "%s"              right_template = "%s"
433              params = (right,)              params = (right,)
434    
435          query = "SELECT gid FROM %s WHERE %s %s %s ORDER BY gid;" \          query = "SELECT %s FROM %s WHERE %s %s %s ORDER BY %s;" \
436                  % (self.quoted_tablename, left.quoted_name, comparison,                  % (self.quoted_id_column, self.quoted_tablename,
437                     right_template)                     left.quoted_name, comparison, right_template,
438                       self.quoted_id_column)
439    
440          cursor = self.db.cursor()          cursor = self.db.cursor()
441          cursor.execute(query, params)          cursor.execute(query, params)
# Line 389  class PostGISShapeStore(PostGISTable): Line 486  class PostGISShapeStore(PostGISTable):
486    
487      """Shapestore interface to a table in a PostGIS database"""      """Shapestore interface to a table in a PostGIS database"""
488    
489      def __init__(self, db, tablename, geometry_column = None):      def __init__(self, db, tablename, id_column = "gid",
490                     geometry_column = None):
491          """Initialize the PostGISShapeStore.          """Initialize the PostGISShapeStore.
492    
493          The db parameter should be an instance of PostGISConnection and          The db parameter should be an instance of PostGISConnection and
494          tablename the name of a table in the database represented by db.          tablename the name of a table in the database represented by db.
495    
496            The id_column parameter should be the name of a column in the
497            table that can be used to identify rows.  The column must have
498            the type integer and be unique and not null.
499    
500          The geometry_column paramter, if given, should be the name of          The geometry_column paramter, if given, should be the name of
501          the geometry column to use.  If the name given is not a geometry          the geometry column to use.  If the name given is not a geometry
502          column, raise a ValueError.          column, raise a ValueError.
# Line 405  class PostGISShapeStore(PostGISTable): Line 507  class PostGISShapeStore(PostGISTable):
507          """          """
508          self.geometry_column = geometry_column          self.geometry_column = geometry_column
509          self.geometry_column_was_given = geometry_column is not None          self.geometry_column_was_given = geometry_column is not None
510          PostGISTable.__init__(self, db, tablename)          PostGISTable.__init__(self, db, tablename, id_column)
511    
512          # For convenience, we have a quoted version of the geometry          # For convenience, we have a quoted version of the geometry
513          # column in self.quoted_geo_col          # column in self.quoted_geo_col
# Line 423  class PostGISShapeStore(PostGISTable): Line 525  class PostGISShapeStore(PostGISTable):
525      def _create_col_from_description(self, index, description):      def _create_col_from_description(self, index, description):
526          """Extend the inherited method to find geometry columns          """Extend the inherited method to find geometry columns
527    
528          If the column indicated by the paramters is a geometry column,          If the column indicated by the parameters is a geometry column,
529          record its name in self.geometry_column and a quoted version in          record its name in self.geometry_column and a quoted version in
530          self.quoted_geo_col.  In any case return the return value of the          self.quoted_geo_col.  In any case return the return value of the
531          inherited method.          inherited method.
# Line 460  class PostGISShapeStore(PostGISTable): Line 562  class PostGISShapeStore(PostGISTable):
562          """          """
563          return None          return None
564    
565        def GeometryColumn(self):
566            """Return the column description object for the geometry column
567    
568            There's currently no FIELDTYPE constant for this column, so the
569            return value is not a regular column object that could also be
570            returned from e.g. the Column() method.  Only the name attribute
571            of the return value is meaningful at the moment.
572            """
573            return PostGISColumn(self.geometry_column, None, None)
574    
575      def ShapeType(self):      def ShapeType(self):
576          """Return the type of the shapes in the shapestore."""          """Return the type of the shapes in the shapestore."""
577          cursor = self.db.cursor()          cursor = self.db.cursor()
# Line 505  class PostGISShapeStore(PostGISTable): Line 617  class PostGISShapeStore(PostGISTable):
617    
618      def Shape(self, shapeid):      def Shape(self, shapeid):
619          cursor = self.db.cursor()          cursor = self.db.cursor()
620          cursor.execute("SELECT AsText(%s) FROM %s WHERE gid=%d"          cursor.execute("SELECT AsText(%s) FROM %s WHERE %s=%d"
621                         % (self.quoted_geo_col, self.quoted_tablename, shapeid))                         % (self.quoted_geo_col, self.quoted_tablename,
622                              self.quoted_id_column, shapeid))
623          wkt = cursor.fetchone()[0]          wkt = cursor.fetchone()[0]
624          cursor.close()          cursor.close()
625          return PostGISShape(shapeid, wkt)          return PostGISShape(shapeid, wkt)
626    
627      def AllShapes(self):      def AllShapes(self):
628          cursor = self.db.cursor()          cursor = self.db.cursor()
629          cursor.execute("SELECT gid, AsText(%s) FROM %s ORDER BY gid"          cursor.execute("SELECT %s, AsText(%s) FROM %s ORDER BY %s"
630                         % (self.quoted_geo_col, self.quoted_tablename))                         % (self.quoted_id_column, self.quoted_geo_col,
631                              self.quoted_tablename, self.quoted_id_column))
632          while 1:          while 1:
633              result = cursor.fetchone()              result = cursor.fetchone()
634              if result is None:              if result is None:
# Line 530  class PostGISShapeStore(PostGISTable): Line 644  class PostGISShapeStore(PostGISTable):
644                  % (left, bottom, left, top, right, top, right, bottom,                  % (left, bottom, left, top, right, top, right, bottom,
645                     left, bottom))                     left, bottom))
646          cursor = self.db.cursor()          cursor = self.db.cursor()
647          cursor.execute("SELECT gid, AsText(%s) FROM %s"          cursor.execute("SELECT %(gid)s, AsText(%(geom)s) FROM %(table)s"
648                       " WHERE %s && GeometryFromText('%s', %d) ORDER BY gid"                       " WHERE %(geom)s && GeometryFromText('%(box)s', %(srid)d)"
649                         % (self.quoted_geo_col, self.quoted_tablename,                         " ORDER BY %(gid)s"
650                            self.quoted_geo_col, geom, self.srid))                         % {"table": self.quoted_tablename,
651                              "geom": self.quoted_geo_col,
652                              "gid": self.quoted_id_column,
653                              "box": geom,
654                              "srid": self.srid})
655          while 1:          while 1:
656              result = cursor.fetchone()              result = cursor.fetchone()
657              if result is None:              if result is None:
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