Querying a Database from a session bean using JDBC
Fiona Healy
Greenhorn
Joined: Jan 27, 2005
Posts: 21
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hi,
I am developing an application that requires the querying of an external database i.e. user requests a number of fields which are stored in the applications database and these are then used to query a second database for the actual values. If anyone can understand what i am talking about, can you direct me as to whats the best approach to doing this. I am using MySQL DB and have been advised to use JDBC in a session bean?
Fiona, Basically you have two queries. So the high level approach is: 1) Query external database (database 1) 2) Loop through result set and store fields in variables (or List if multiple rows.) 3) Build sql string for second query. I recommend using prepared statements so you can easily substitute in the values. 4) Run second query (database 2) 5) Loop through result set and process actual values
The logic behind separating the queries is so you can close the first connection sooner. Take a look at Sun's JDBC tutorial to get started with JDBC.
For the future, I recommend posting this type of question in the JDBC forum since it is more about JDBC than session beans.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus
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