You can use the Migrate Storage geoprocessing tool to migrate existing binary, spatial, or raster columns from one storage type to another. This is done by specifying a configuration keyword that contains an ATTRBUTE_BINARY, GEOMETRY_STORAGE, or RASTER_STORAGE parameter set to the new storage type to which you want to convert the data.
It is important to create the configuration keyword to include the correct parameter and value. If you specify a keyword with incorrect or missing information, the information is read from the DEFAULTS keyword. Esri recommends that you create a custom keyword specifically for the migration. Be sure the keyword contains the parameter and value to which you are migrating the data, as well as a UI_TEXT parameter. The UI_TEXT parameter makes the keyword available to ArcGIS clients.
The following are the supported migration paths for each database management system (DBMS):
LONG RAW to BLOB
LONG RAW (SDEBINARY) to BLOB (SDELOB)
LONG RAW (SDEBINARY) to ST_GEOMETRY
BLOB (SDELOB) to ST_GEOMETRY
SDO_GEOMETRY to ST_GEOMETRY
LONG RAW to BLOB
LONG RAW to ST_RASTER*
BLOB to ST_RASTER*
BYTEA to ST_RASTER*
IMAGE to ST_RASTER*
SDEBINARY to GEOMETRY
SDEBINARY to GEOGRAPHY
OGCWKB to GEOMETRY
OGCWKB to GEOGRAPHY
Why would I migrate data?
There are two reasons you would migrate your data:
- To access your spatial or raster data using structured query language (SQL)
- To move from a data type that may not be supported in a future to one that is supported
Access data using SQL
Accessing the information in a geodatabase via SQL allows external applications (those not developed in an ArcObjects environment) to work with the tabular data managed by the geodatabase. If these applications need to access spatial or raster data in the geodatabase, you must store your spatial or raster data in data types that allow SQL access. For example, using the ST_Raster storage type allows you to access your raster data with SQL, something that you cannot do easily if your raster data is stored in a BLOB, LONG RAW, IMAGE, BINARY, or BYTEA field.
Move from types that may not be supported in future releases
Oracle is recommending the use of BLOB or BFILE data types instead of LONG RAW data types in its databases. Although LONG RAW columns are still supported, if you have LONG RAW attribute, geometry, or raster fields in your current geodatabase in Oracle, you should migrate them to a different format in preparation for when they are not supported.
The storage for the attribute, geometry, and raster columns in a geodatabase is controlled by the DBTUNE parameters ATTRIBUTE_BINARY, GEOMETRY_STORAGE, and RASTER_STORAGE, respectively. The defaults for these parameters under the DBTUNE DEFAULTS configuration keyword are different depending on which release of ArcGIS you were using when you created your geodatabase. The following table shows the default setting under the DEFAULTS keyword in the DBTUNE table of geodatabases in Oracle.
|Default at ArcGIS 9.3 and later releases
|Default at ArcGIS 9.2
|Default prior to ArcGIS 9.2
LONG RAW (SDEBINARY)
LONG RAW (SDEBINARY)
Data created in new (not upgraded) 9.3 or later release geodatabases using the default parameter settings do not use the LONG RAW storage type. However, any existing data created with any or all of these parameters set to LONG RAW or any new data in upgraded geodatabases that have these parameters set to LONG RAW will still contain LONG RAW columns. To change the data types for these columns, you must alter your DBTUNE settings and migrate the data.
Beginning with ArcGIS 10.1, feature classes created in geodatabases in SQL Server use the Microsoft geometry type be default. To move your existing feature classes to the geometry storage type, use the Migrate Storage geoprocessing tool or a Python script.
Before you migrate...
The following conditions must be met before you convert your data:
- You must make a backup of the data before you migrate it.
- If you are converting the spatial column data type, the data must be stored in high precision. If your data is currently stored with basic precision, you must first migrate it to high precision before you migrate the storage type. Use the Upgrade Spatial Reference geoprocessing tool to upgrade to high precision.
- The table or feature class must be registered with the geodatabase.
- The configuration keyword you specify when migrating the data type has to contain the correct value for the GEOMETRY_STORAGE, ATTRIBUTE_BINARY, or RASTER_STORAGE parameter. For example, if you want to migrate a LONG RAW geometry column to ST_GEOMETRY, but you specify a keyword that has the GEOMETRY_STORAGE parameter set to SDO_GEOMETRY, the migration will fail because that is not a supported migration path.
- You must be logged in as the owner of the table that contains the column being migrated.
- Migration of a feature class to the SQL Server GEOGRAPHY type requires that the data be in one of the geographic coordinate systems supported by the GEOGRAPHY type.
- If your geodatabase is in SQL Server 2008 or 2008 R2, feature classes migrated to the SQL Server GEOGRAPHY type cannot contain z- or m-coordinate values.