ORA-02070: Error when updating a SQL Server table thru an Oracle View

Question

I have a SQL Server table TIMESHEET which contains a number of VARCHAR and NUMERIC columns plus a DATETIME column.
Only the DATETIME column is giving me trouble.
On the ORACLE side I have a view which selects from the SQL Server table but in order to get the SELECT to work, I had to either put a CAST or TO_DATE function call around the DATETIME field
Below is the relevant part of the 2 view definitions I have tried
create view TIMESHEET as
SELECT
"TsKeySeq" as TS_KEY_SEQ,
"EmployeeNo" as EMPLOYEE_NO,
CAST("PeriodEnding" AS DATE) as PERIOD_ENDING,
. . . (more columns - not relevant)
FROM [email protected];
An update to the view generates this message
ORA-02070: database OLEMSQLPSANTDAS6 does not support CAST in this context
create view TIMESHEET as
SELECT
"TsKeySeq" as TS_KEY_SEQ,
"EmployeeNo" as EMPLOYEE_NO,
TO_DATE("PeriodEnding") as PERIOD_ENDING,
. . . (more columns - not relevant)
FROM [email protected];
An update to the view generates this message
ORA-02070: database OLEMSQLPSANTDAS6 does not support TO_DATE in this context
If I don't include either the TO_DATE() or CAST() then I get
Select Error: ORA-28527: Heterogeneous Services datatype mapping error
ORA-02063:preceding line from OLEMSQLSANTDAS6
Does anyone have any idea how to update a SQL Server DATETIME column thru an ORACLE view?

Answer 1

You can't cast accross heterogenious databases and there is no need to. HSODBC treats SQL Server DATETIME column as DATE. For example, I have SQL Server table:
CREATE TABLE [Ops].[T_JobType](
     [JobType] [varchar](50) NOT NULL,
     [JobDesc] [varchar](200) NULL,
     [InsertDt] [datetime] NOT NULL CONSTRAINT [InsertDt_00000006]  DEFAULT (getdate()),
     [InsertBy] [varchar](128) NOT NULL CONSTRAINT [InsertBy_00000006]  DEFAULT (user_name()),
     [LastUpdated] [datetime] NOT NULL CONSTRAINT [LastUpdated_00000006]  DEFAULT (getdate()),
     [LastUpdatedBy] [varchar](128) NOT NULL CONSTRAINT [LastUpdatedBy_00000006]  DEFAULT (user_name()),
CONSTRAINT [T_JobType_PK] PRIMARY KEY CLUSTERED
     [JobType] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON, FILLFACTOR = 100) ON [DATA01FG]
) ON [DATA01FG]Now on Oracle side I do:
SQL> desc "Ops"."T_JobType"@pbods
Name                                      Null?    Type
JobType                                   NOT NULL VARCHAR2(50)
JobDesc                                            VARCHAR2(200)
InsertDt                                  NOT NULL DATE
InsertBy                                  NOT NULL VARCHAR2(128)
LastUpdated                               NOT NULL DATE
LastUpdatedBy                             NOT NULL VARCHAR2(128)
SQL> select "InsertDt" from "Ops"."T_JobType"@pbods;
InsertDt
18-AUG-08
09-OCT-08
22-OCT-09
18-AUG-08
19-NOV-08
SQL> SY.