TEXT and BYTE (LOB) types
Informix®
Informix provides the TEXT,
BYTE, CLOB and BLOB data types to store very
large texts or binary data.
Legacy Informix 4GL applications typically use the
TEXT and BYTE types.
Genero BDL does not support the Informix
CLOB and BLOB types.
IBM® DB2®
IBM DB2 supports the
LONG VARCHAR/CLOB and BLOB/VARGRAPHIC/DBCLOB types for large
objects storage.
Additionally, depending on the nchar_mapping DB2 database configuration
parameter, the NCLOB type name can be used as a synonym for CLOB
with CODEUNITS32 units specifier, or as DBCLOB with
CODEUNITS32 or CODEUNITS16 units specifier.
CREATE TABLE tab1 ( ... tx CLOB(200K) ... )With DB2 LUW 11.5, the default maximum size of CLOB/DBCLOB types is 1,048,576
(1M) code units. For the BLOB type, the default is 1,048,576 (1M) bytes.
Solution
The DB2 database interface can convert BDL
TEXT data to DB2 CLOB and
BYTE data to DB2 BLOB.
In programs, when creating a table with TEXT or BYTE columns,
the ODI driver will convert the type to the native DB2 SQL types CLOB,
NCLOB or BLOB.
Based on the FGLPROFILE entry dbi.database.dbname.ifxemul.nationalchars, the
TEXT type name in SQL statements is converted to CLOB or to
NCLOB DB2 types, which is then interpreted by DB2 to CLOB or
DBCLOB types, depending on the nchar_mapping database
parameter.
TEXT/BYTE SQL types are mapped to DB2 CLOB, NCLOB and BLOB types with a size
of 500K. A different size can be specified for all TEXT and BYTE
columns created from programs, with the dbi.database.dbname.ifxemul.datatype.typename.size
FGLPROFILE
entries:dbi.database.dsname.ifxemul.datatype.text.size = "500K"
dbi.database.dsname.ifxemul.datatype.byte.size = "2M"/* fglhint_no_ifxemul */ SQL
hint:EXECUTE IMMEDIATE "/* fglhint_no_ifxemul */ ... notes DBCLOB(200K CODEUNITS32) ..." TEXT and
BYTE types translation can be controlled with the following FGLPROFILE
entries:dbi.database.dsname.ifxemul.datatype.text = { true | false }
dbi.database.dsname.ifxemul.datatype.byte = { true | false }