Passthrough mode

Passthrough mode allows a DirectConnect for Oracle client to interact directly with an Oracle database using native Oracle SQL. When DirectConnect for Oracle is operating as a standalone gateway, clients are automatically put into passthrough mode. When used with Adaptive Server Enterprise, DirectConnect for Oracle performs Transact-SQL parsing.

In passthrough mode, the client program issues Oracle SQL statements directly to the Oracle database, and the results are converted into a form that the Open Client interface understands.

When in passthrough mode, Oracle datatypes are converted to the following Open Client datatypes:

**Table 3-1: Oracle-to-Adaptive Server datatype conversions for numeric data with create proxy_table**
Oracle datatype	Open Client datatype number_mode=0	Open Client datatype number_mode=1	Open Client datatype number_mode=2
number(1,0)	tinyint	tinyint	numeric (1,0)
number(2,0)	tinyint	tinyint	numeric (2,0)
number(3,0)	smallint	smallint	numeric (3,0)
number(4,0)	smallint	smallint	numeric (4,0)
number(5,0)	int	int	numeric (5,0)
number(p,0) where 6 <= p <= 9	int	int	numeric (p,0)
number(p,0) where 10 <= p <= 38	numeric (p,0)	numeric (p,0)	numeric (p,0)
number(p,s) where 1 <= p <= 38 and 1 <= s <= 38	numeric (p,s)	numeric (p,s)	numeric (p,s)

**Table 3-2: Oracle-to-Adaptive Server datatype conversions for non-numeric data with create proxy_table**
Oracle datatype	Adaptive Server datatype
nchar(n)	varchar(n)
float	float
char(n)	char(n)
varchar(n)	varchar(n)
nvarchar2(n)	varchar(n)
raw(n)	binary(n)
clob	text
nclob	text
blob	image
date	datetime
bfile	image
long	text
long raw	image
timestamp	datetime