13.4.7 Populating Spatial Columns

After you have created spatial columns, you can populate them with spatial data.

Values should be stored in internal geometry format, but you can convert them to that format from either Well-Known Text (WKT) or Well-Known Binary (WKB) format. The following examples demonstrate how to insert geometry values into a table by converting WKT values to internal geometry format:

• Perform the conversion directly in the INSERT statement:

  INSERT INTO geom VALUES (ST_GeomFromText('POINT(1 1)'));
  
  SET @g = 'POINT(1 1)';
  INSERT INTO geom VALUES (ST_GeomFromText(@g));

• Perform the conversion prior to the INSERT:

  SET @g = ST_GeomFromText('POINT(1 1)');
  INSERT INTO geom VALUES (@g);

The following examples insert more complex geometries into the table:

SET @g = 'LINESTRING(0 0,1 1,2 2)';
INSERT INTO geom VALUES (ST_GeomFromText(@g));

SET @g = 'POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5))';
INSERT INTO geom VALUES (ST_GeomFromText(@g));

SET @g =
'GEOMETRYCOLLECTION(POINT(1 1),LINESTRING(0 0,1 1,2 2,3 3,4 4))';
INSERT INTO geom VALUES (ST_GeomFromText(@g));

The preceding examples use ST_GeomFromText() to create geometry values. You can also use type-specific functions:

SET @g = 'POINT(1 1)';
INSERT INTO geom VALUES (ST_PointFromText(@g));

SET @g = 'LINESTRING(0 0,1 1,2 2)';
INSERT INTO geom VALUES (ST_LineStringFromText(@g));

SET @g = 'POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5))';
INSERT INTO geom VALUES (ST_PolygonFromText(@g));

SET @g =
'GEOMETRYCOLLECTION(POINT(1 1),LINESTRING(0 0,1 1,2 2,3 3,4 4))';
INSERT INTO geom VALUES (ST_GeomCollFromText(@g));

A client application program that wants to use WKB representations of geometry values is responsible for sending correctly formed WKB in queries to the server. There are several ways to satisfy this requirement. For example:

• Inserting a POINT(1 1) value with hex literal syntax:

  INSERT INTO geom VALUES
  (ST_GeomFromWKB(X'0101000000000000000000F03F000000000000F03F'));

• An ODBC application can send a WKB representation, binding it to a placeholder using an argument of BLOB type:

  INSERT INTO geom VALUES (ST_GeomFromWKB(?))

  Other programming interfaces may support a similar placeholder mechanism.

• In a C program, you can escape a binary value using mysql_real_escape_string_quote() and include the result in a query string that is sent to the server. See mysql_real_escape_string_quote().