Retrieve data from a synonym in oracle database through db connect

Question

Hi Everyone,
I have created certain synonym for some tables in oracle. I want to retrieve data from it through db connect but where through source system and then selecting database tables, only tables and views are available.
Synonyms are not available to create data sources and retrieve the data from it. Why is it so. Is this a limitation of db connect.
Can anyone please let me know about it.
Thanks,
Joshua.

Answer 1

Hi,
You want to import data from an external Oracle database into your BW 3.X. To do this, you can connect the external database to the BW 3.X release as a source system using the external database connect. BW 3.X here represents BW 3.0, BW 3.1 and BW 3.5 because in other (DB relevant) parts, all 3 versions are based on the same source code.
General information
The above function allows you to load data from an external Oracle database (not a BW database) into your BW 3.0 system.
There may also be constellations which cannot be used directly through the DB Connect access. However, it should be possible to find an adequate, customer-specific solution for most of these scenarios.
In such situations, the resulting work falls into the area of Consulting and cannot be handled via Support.
Successful implementation of a connection requires corresponding expertise and experience in the use of the source database in the areas:
                - Tools
                - SQL syntax
                - DB-specific functions
Corresponding knowledge of the source application is also required to ensure that semantically relevant data arrives in the BW system.
Procedure
You should execute the following steps to connect the source system (Q) to the BW system (BW):
Installing the client software on an BW application server
                     Of course, you only need to install the client software if you are using BW with a non-Oracle database.
                     Use the Oracle setup program on the database CD (runInstaller on Unix) to start the OracleInstaller. Follow the program instructions and the DB installation instructions to install the Oracle Client software on BW.
Testing connection setup from BW to Q
                     After you install the client software on BW, try to set up a connection from BW to the server on Q. You may need to adjust the tnsnames.ora or sqlnet.ora files for this, to introduce the Oracle systems (to which contact should be made) to BW. You can test the connection by executing the command "tnsping QDB" on BW to check whether the client has established contact to the QDB database on the Q system.
Creating a separate U user in Q
                     We recommend that you create a separate U user in Q for connection to BW. This means that authorization and administration questions can be solved centrally.
Displaying data sources in Q for the U user
                     To provide U data for users other than U, you can create views on other user tables as user U:
                     CREATE OR REPLACE VIEW viewname AS
                       SELECT * FROM QDB.tablename
                     You may have to grant SELECT privileges to user U in the QDB schema:
                        GRANT select ON QDB.tablename TO U
                     Of course, you can also restrict or reformat data in the view arrangement (for example, change from internal date format into the SAP date format). JOIN operations using several tables are also available.
                     !!! Synonyms do not yet work!!!
                     Synonyms that you can create as described below are another option for providing a complete table for the user U:
                       CREATE SYNONYM synoname FOR QDB.tablename
                     !!! Synonyms do not (yet) work!!!
                     After you have displayed the require data for user U, you can simply use
                       SELECT * FROM <view or table>
                     on the Q system to check which data is returned.
                     You can now open a link to Q as user U in the BW system with SQLPLUS and check, using the same SELECT, whether this data is also seen in the Oracle client. If this is not the case, there is probably a connection problem.
Creating a connection from BW to Q in BW
Including data sources of user U user in Q in BW.
Solution
Supported BW, Basis and BW 3.0B database versions, Basis 6.20 Support Package 2 (or higher)
      Oracle 8.1 (or higher, see below)
Possible problems
- Synonyms do not (yet) work!
Up to now, only tables and views have been used as data sources for the DB Connect from the R3 Basis. As soon as synonyms are also used in the Basis, you will be able to convert created views (or even replicated tables) to synonyms as a workaround.
With Basis 6.40 at the earliest, therefore as of BW 3.5, you will also be able to use synonyms. Until then, the following will help:
  CREATE VIEW <view_on_synonym> AS SELECT * FROM <synonym>
- The source DB must have at least the release version of the BW DB.
Oracle only ensures the support of client-server links if the version of the client is not higher than that of the server. So if BW has Oracle version 8.1 and, as in the case of Dbconnect, is run as a client against the server of the source database, the source database must have at least release Oracle 8.1 or higher.
Of course, you have the option to install the Oracle client software of a lower version and then use this for the DB connect. This is also the procedure used to work with a DB connect on external databases of other vendors.
Furthermore, the implementation of the DBconnect function in BW uses SAP Basis functions. Specifications of Oracle 8.1 database catalogs are used here. The source database must therefore have at least Version 8.1.
- Oracle Client Software Version
If you want to connect from an Oracle BW DB to an Oracle source DB, for the DB connect you naturally use the client software that you already installed on each application server.
If you want to connect from a non-Oracle BW DB to an Oracle source DB, check item 3 of note 521230 to see which Oracle client software version is released with your BW R3 kernel and use this version.
- Date and time fields in Oracle and their conversion into SAP-compatible column formats
Example with a DATE field:
Since a SAP table does not have a DATE field (date values are NUMC(8) and time specifications are NUMC(6)), we will use the Oracle DBA_TABLES system table as an example.
    SQL> desc dba_tables;
The Oracle DBA_TABLES system table has a LAST_ANALYZED field. This is a DATE type field and is recognized as a date field of 7 characters by DBA_CONNECT. However, the import does not work because the DATE is a 7-byte conglomerate of "...century, year, month, date, hour, minute and second." (extract from the Oracle documentation).
To make this DATE field legible for DB connect, you must use the TO_CHAR function in a VIEW. This should display the following examples:
SQL> select LAST_ANALYZED from dba_tables
      where table_name like 'RS%' and rownum < 10 ;
The formatting used here is the default used implicitly by SQLPLUS.
SQL> select  to_char(LAST_ANALYZED,'YYYYMMDD') as dat from dba_tables where table_name like 'RS%' and rownum < 10 ;
The result now has the SAP compatible format YYYYMMDD and should be loaded correctly by the DB connect as a date.
SQL> select  to_char(LAST_ANALYZED,'HH24MISS') as tim from dba_tables where table_name like 'RS%' and rownum < 10 ;
The result now has the SAP compatible format HHMMSS and should be loaded correctly by the DB connect as a time.
You can use the following example for more detailed experiments:
SQL> select  to_char(
       TO_DATE('03-FEB-2001 04:05:06','DD-MON-YYYY HH24:MI:SS'),
       'YY-MM-DD HH24-MI-SS') as datim from dual;
with the result:
  DATIM
  01-02-03 04-05-06
When you create a VIEW and use the TO_CHAR function (or other functions), you should easily be able to avoid problems with the interpretation of date/time specifications (and other reformatting).
Details about the functions and the formats are contained in the Oracle documentation.
- Special characters
A words that contain special characters can only be imported correctly if the code pages in BW and in the source system are identical. If the code pages are not the same, DB Connect can be used if the characters to be imported appear under the first 127 characters of the character set.
The use of multibyte code pages in the source system for saving data using character sets with more than 256 characters (Kanji, Katakana, Hiragana, Korean, Chinese, Tagalog, Khmer, Arabic, Cherokee, and so on) can cause the characters to become corrupt.
For questions concerning the code pages, also refer to the FAQ note 606359 and question/answer 19 that appears there.