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.
Microsoft™ SQL Server
Microsoft SQL Server provides the
VARCHAR(MAX), NVARCHAR(MAX) and VARBINARY(MAX)
data types to store large object data.
The SQL Server TEXT, NTEXT and IMAGE data
types still exist, but are considered as obsolete and will be removed in a future version.
In SQL Server, the VARCHAR(MAX), NVARCHAR(MAX) and
VARBINARY(MAX) types have a limit of 2 gigabytes (2^31 -1 actually).
Solution
In Genero programs connecting to SQL Server, the TEXT and BYTE
data types of DDL statements such as CREATE TABLE are respectively converted to
VARCHAR(MAX) and VARBINARY(MAX) types.
SQL Server database drivers make the appropriate bindings to use TEXT and
BYTE Genero types as SQL parameters and fetch buffers, and can be used for SQL
SERVER text, image or VARCHAR(MAX), NVARCHAR(MAX) and
VARBINARY(MAX) columns.
To store TEXT data, when using a multibyte character set (such as UTF-8), define
database columns as NVARCHAR(MAX). When using a single-byte character set in you
application (like ISO-8859-15), the column type can be VARCHAR(MAX).
CREATE TABLE), the
TEXT type name is left untouched. To force the ODI drivers to replace
TEXT by the NVARCHAR(MAX) type name when the locals is multibyte,
set the dbi.database.dsname.ifxemul.nationalchars FGLPROFILE
entry to true (default is
false):dbi.database.dsname.ifxemul.nationalchars = true - With SQL Server ODI drivers,
dbi.database.dsname.ifxemul.nationalcharswill only take effect, if the current application locale is multibyte (typically, UTF-8) - The
dbi.database.dsname.ifxemul.nationalcharsparameter is ignored, if the switch corresponding to the character type name (dbi.database.dsname.datatype.{char|varchar|text}) is set tofalse. - With the SNC ODI
driver, to have
dbi.database.dsname.ifxemul.nationalcharstake effect, the wide-char mode must be enabled (this is the default with multibyte character sets).
Genero TEXT/BYTE program variables and the SQL Server large object types have
the same a limit of 2 gigabytes.
SET/IF statements and
produces a result set with LOBs, the LOB columns must appear at the end of the
SELECT list. If LOB columns are followed by other columns with regular types, the
fetching rows will fail. Using SET NOCOUNT ON in the stored procedure does not
help, because the cursor type is changed from a server cursor to a default result set cursor.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 }