DB2 Spatial

Driver short name

DB2

This driver implements support for access to spatial tables in the IBM DB2 for Linux, Unix and Windows (DB2 LUW) and the IBM DB2 for z/OS relational databases using the default ODBC support incorporated into GDAL.

The documentation for the DB2 spatial features can be found online for DB2 for z/OS and DB2 LUW

This driver is currently supported only in the Windows environment.

Driver capabilities

Supports Create()

This driver supports the GDALDriver::Create() operation

Supports Georeferencing

This driver supports georeferencing

Connecting to a database

To connect to a DB2 datasource, use a connection string specifying the database name, with additional parameters as necessary. The connection strings must be prefixed with ‘DB2ODBC:’.
You can specify either a DSN that has been registered or use parameters that specify the host, port and protocol.
DB2ODBC:database=dbname;DSN=datasourcename

or

DB2ODBC:database=dbname;DRIVER={IBM DB2 ODBC DRIVER};Hostname=hostipaddr;PROTOCOL=TCPIP;port=db2port;UID=myuserid;PWD=mypw

The following custom parameters can also be used in the following syntax:

  • Tables=schema1.table1(geometry column1),schema2.table2(geometry column2): By using this parameter you can specify the subset of the layers to be used by the driver. If this parameter is not set, the layers are retrieved from the DB2GSE.ST_GEOMETRY_COLUMNS metadata view. You can omit specifying the schema and the geometry column portions of the syntax.

The parameter names are not case sensitive in the connection strings.

Specifying the Database parameter is required by the driver in order to select the proper database.

Layers

By default the DB2 driver will only look for layers that are registered in the DB2GSE.ST_GEOMETRY_COLUMNS metadata table.

SQL statements

The DB2 driver passes SQL statements directly to DB2 by default, rather than evaluating them internally when using the ExecuteSQL() call on the OGRDataSource, or the -sql command option to ogr2ogr. Attribute query expressions are also passed directly through to DB2. It’s also possible to request the OGR DB2 driver to handle SQL commands with the OGR SQL engine, by passing “OGRSQL” string to the ExecuteSQL() method, as the name of the SQL dialect.

The DB2 driver in OGR supports the OGRLayer::StartTransaction(), OGRLayer::CommitTransaction() and OGRLayer::RollbackTransaction() calls in the normal SQL sense.

Creation Issues

This driver doesn’t support creating new databases. Use the DB2 command line or tools like IBM Data Studio to create the database. It does allow creation of new layers within an existing database.

Layer Creation Options

  • OVERWRITE: This may be “YES” to force an existing layer of the desired name to be destroyed before creating the requested layer.

  • LAUNDER: This may be “YES” to force new fields created on this layer to have their field names “laundered” into a form more compatible with DB2. This converts to lower case and converts some special characters like “-” and “#” to “_”. If “NO” exact names are preserved. The default value is “YES”. If enabled the table (layer) name will also be laundered.

  • PRECISION: This may be “YES” to force new fields created on this layer to try and represent the width and precision information, if available using numeric(width,precision) or char(width) types. If “NO” then the types float, int and varchar will be used instead. The default is “YES”.

  • DIM={2,3}: Control the dimension of the layer. Defaults to 2.

  • GEOM_NAME: Set the name of geometry column in the new table. If omitted it defaults to ogr_geometry.

  • SCHEMA: Set name of schema for new table. The default schema is that of the userid used to connect to the database

  • SRID: Set the spatial reference id of the new table explicitly. The corresponding entry should already be added to the spatial_ref_sys metadata table. If this parameter is not set the SRID is derived from the authority code of source layer SRS.

Spatial Index Creation

By default the DB2 driver doesn’t add spatial indexes to the tables during the layer creation. Spatial indexes should be created using the DB2 CREATE INDEX command.

Examples

Creating a layer from an OGR data source

ogr2ogr -overwrite  DB2ODBC:database=sample;DSN=sampDSN zipcodes.shp

Connecting to a layer and dump the contents

ogrinfo -al DB2ODBC:database=sample;DSN=sampDSN;tables=zipcodes