RE: Question for the JDBC experts, Re: getPrimaryKeys

RPG connects to Java through a built-in JNI interface, so I'm guessing you can use the JNI datatype specs as a guide.

http://docs.oracle.com/javase/1.5.0/docs/guide/jni/spec/types.html

Boolean is an eight bit field with the lowest order bit set to 1 for true and 0 for false. One way would be to pass a 1-character field. BITOFF '01234567' for false, same with BITON '7' for true. Probably a lot easier to set up a couple of constants in D specs intialized to X'00' and X'01'

-----Original Message-----
From: java400-l-bounces@xxxxxxxxxxxx [mailto:java400-l-bounces@xxxxxxxxxxxx] On Behalf Of James H. H. Lampert
Sent: Tuesday, March 19, 2013 3:54 PM
To: Java Programming on and around the IBM i
Subject: Re: Question for the JDBC experts, Re: getPrimaryKeys

On 3/19/13 12:22 PM, Dan Kimmel wrote:

A primary key describes the table's uniqueness constraint and implies no order. As it happens, DB2 for i will build an index corresponding to the primary key simply because that's the fastest way for it to be able to check if there's already an instance of the key in the table. Indexes do have order. Indexes can also be created optimized for ascending or descending order, though most of the time an index can be read as fast backwards as forwards.

You can use DatabaseMetaData.getIndexInfo() against a table and match the resulting list against the primary key meta data to find the (one of the) indexes that match the primary key.

Does that help?

It might. But I'm not entirely sure how to pull it into JDBCR4: it takes two boolean parameters, and I'm not sure how to prototype a boolean parameter to a Java call in RPG.

When I pulled in getPrimaryKeys, I pulled it in thusly:

D getPrimaryKeys...
D PR ExtProc(*JAVA:
D 'java.sql.DatabaseMetaData':
D 'getPrimaryKeys')
D like(ResultSet)
D catalog like(jString) const
D schema like(jString) const
D table like(jString) const

but I see that getIndexInfo has two boolean parameters in addition to the ones for getPrimaryKeys.

Would I pull them into JDBCR4 as type "1N"?

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JHHL
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