Regarding JDBC Adapter in SAP XI

Question

Hi
I have done one scenario in SAP XI using JDBC Lookup it is working fine thanks for all who were helped me ......
I need a clarification on following
What is
Generic Lookup API
Special Lookup API
and while i am  configuring i have given
Persistence : Local
Confilct Resolution : Redo
In what situation we will give  Presistence : Local and in what situation we will give Persistence : Database means i need to know where we will use LOCAL and where we will use DATABASE
and what is the difference between REDO and ERROR...........?
In Message Protocol we have two protocols
      XML SQL Format
      Native XML Format
what is the difference between these two
I have gone through some blogs which i got in my previous posts but i am not able to understand clearly..... can any one clarify my doubts please........?
Best Regards
Ravi Shanakar B

Answer 1

Generic Lookup API
In the case of generic access, before executing the lookup, developers first need to both build the payload that the adapter expects and parse the result payload themselves.
To access an application system generically, developers use the SystemAccessor class. For generic calls, developers of a method must pass a stream with the payload, which is then sent to the adapter. The result of the call is a payload object, which you can use to both read the payload as a stream and parse the payload.
The generic lookup API is part of the mapping API (see LookupService class in the Javadoc documentation). For more information about these APIs, see SAP Developer Network at https://www.sdn.sap.com/irj/sdn/javadocs
You can obtain the schema to call an RFC by simply importing the RFC into the Integration Repository. (See Importing IDocs and RFCs.)
Special Lookup API
For access using the special lookup API, developers do not require any knowledge of the structure of the payload. Instead, they pass the API string commands that are to be executed in the application system called.
Currently, there is one special lookup API for the JDBC adapter. To use this API, developers use the DataBaseAccessor class instead of the SystemAccessor class.
The special lookup API is part of the mapping API (see the getDataBaseAccessor method of the LookupService class in the Javadoc documentation). For more information about these APIs, see SAP Developer Network at https://www.sdn.sap.com/irj/sdn/javadocs
XML SQL Format
Table values can be inserted, updated, or deleted in one or more tables. In the database, stored procedures can be called using transfer parameters. In the case of synchronous queries, results from database queries or return values of stored procedures can also be transferred.
Native SQL String
An arbitrary SQL statement is expected as the message content. This statement is transferred unaltered to the database for processing
Please see the below link
http://help.sap.com/saphelp_nw2004s/helpdata/en/cf/406642ea59c753e10000000a1550b0/content.htm
http://help.sap.com/saphelp_nw2004s/helpdata/en/64/ce4e886334ec4ea7c2712e11cc567c/content.htm
Regards
Chilla..