CLOB Support in Genexus

Scope

Languages: Java, NET, VFP
DBMS: Oracle (gx 9.0), DB2 UDB (gx X)

Introduction

Until now, LongVarChar's were defined as LONGs within the database. As from GeneXus 9.0 they are defined as CLOB in Oracle and as from GeneXus X as CLOB in DB2 Universal Database.
In GeneXus 9.0 version, Long VarChar type attributes are created as CLOB instead of Long for Oracle (DBMS 8.0 and later versions). This is recommended by Oracle.
In GeneXus X version, Long VarChar type attributes are created as CLOB instead of Long for DB2 UDB.

Description

As it says in Oracle documentation, the LOB datatypes for character data are CLOB and NCLOB. They can store up to 4 gigabytes of character data (CLOB) or national character set data (NCLOB). LOB datatypes are intended to replace the LONG datatype functionality.
The LONG datatype is provided for backward compatibility with existing applications, so Oracle recommends in new applications, to use CLOB and NCLOB datatypes for large amounts of character data.

By using CLOBs many limitations are discarded, as that a table can contain multiple LOB columns but only one LONG column.

See Oracle documentation for further information about clobs:
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96524/c13datyp.htm#3057

Note:
In GeneXus 9.0 Long varchars are created as CLOB by default.
But, for compatibility reasons, in GeneXus 9.0 version, you are able to create Long varchars as LONGs, if you put LongVarCharAsOracleLong=y in config.gx file.
More information..http://www.gxtechnical.com/main/hviewsac.aspx?2,3,14,18551