Configuring Access to connect to Oracle
Configuring Access is just
about as simple as the previous steps. In the next example, I created a new
Access database and used it to read Scott's EMP table. I also updated data and
added a new employee.
As a side note, Oracle has
stated that the Scott schema has become a deprecated feature. It seems that
future releases will be using the sample schemas (HR, SH, etc.) you see
installed when using DBCA. If you want to keep the Scott schema, you can get
its creation scripts from one of two places: ORACLE_HOME\rdbms\admin\utlsampl.sql
and \sqlplus\demo\demobld.sql.
Start Access and create a
new database. Go to File>External Data>Link Tables. In the Link window, you will have to scroll down the list
shown in the Files of Type field. Select ODBC Database as shown in the
screenshot.
Click for larger image
Once you have done that, you
will be prompted to select a data source. Switch tab views to the Machine Data Source tab. Recognize the items in that
list? You should, because it is the same as what you previously saw in the ODBC Data Source Administrator window.
After highlighting your
Oracle database data source, click OK. You will be presented with a list of
tables. You can control-click on tables to add more than one at a time. Shown
below is the area in the list where Scott's tables reside (somewhat towards the
bottom of the list).
I selected BONUS, EMP, DEPT
and SALGRADE. After selecting the tables, you will be ready to access them.
Highlight one (EMP, in this case) and click Open.
The results of querying the
EMP table should look very familiar. In the display shown below, I changed
James' salary to 952 and saved the table.
Did the save (update)
operation take effect? Let's see.
SQL> select * from emp;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN2 SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30
7566 JONES MANAGER 7839 02-APR-81 2975 20
7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-MAY-81 2850 30
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7788 SCOTT ANALYST 7566 19-APR-87 3000 20
7839 KING PRESIDENT 17-NOV-81 5000 10
7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788 23-MAY-87 1100 20
7900 JAMES CLERK 7698 03-DEC-81 952 LOOK HERE 30
7902 FORD ANALYST 7566 03-DEC-81 3000 20
7934 MILLER CLERK 7782 23-JAN-82 1300 10
14 rows selected.
A simple query in SQL*Plus
confirms the update (LOOK HERE was typed in later). That was easy, but what
if I had made a mistake? For example, what happens if I create a new employee,
but violate a constraint? In the screenshot shown below, I attempted to insert
a new employee named Linda Cole, but I used an existing empno. What does Access
tell me about what happened?
The ODBC call failed,
and here is why:
After fixing my mistake, the
save (insert) operation takes place, and a query in SQL*Plus confirms it.
SQL> /
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- ---------- --------- ---------- --------- ---------- ---------- ----------
7369 SMITH CLERK 7902 17-DEC-80 800 20
7499 ALLEN2 SALESMAN 7698 20-FEB-81 1600 300 30
7521 WARD SALESMAN 7698 22-FEB-81 1250 500 30
7566 JONES MANAGER 7839 02-APR-81 2975 20
7654 MARTIN SALESMAN 7698 28-SEP-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-MAY-81 2850 30
7782 CLARK MANAGER 7839 09-JUN-81 2450 10
7788 SCOTT ANALYST 7566 19-APR-87 3000 20
7839 KING PRESIDENT 17-NOV-81 5000 10
7844 TURNER SALESMAN 7698 08-SEP-81 1500 0 30
7876 ADAMS CLERK 7788 23-MAY-87 1100 20
7900 JAMES CLERK 7698 03-DEC-81 952 30
7902 FORD ANALYST 7566 03-DEC-81 3000 20
7934 MILLER CLERK 7782 23-JAN-82 1300 10
***** 7935 COLE LINDA 7839 01-MAY-04 4000 30
15 rows selected.
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