在Java预准备语句中使用DB2序列

Question

I want to get the next value of a db2 sequence if the placeholder in the preparedstatement is 0 . How can i do that .

PreparedStmt.setLong(1, attributeID);

So here if attributeID is 0 , i want to get the next value from the sequence, other wise i use the attribute ID .

I tried using

PreparedStmt.setObject(1, attributeID > 0 ? attributeID : next val for my seq);

but this does not work !

Answer 1

It's to easy, just get the sequence like you get a result set with executeQuery() method. Then the select statement is:

SELECT SEQ_NAME.NEXTVAL FROM SYSIBM.SYSDUMMY1

The other part is an if sentence. That's all you need to do.

Answer 2

You can declare the primary key column as

ATTRIBUTEID BIGINT GENERATED BY DEFAULT AS IDENTITY

To insert a row with a specific value, include the primary key column in the sql and set its value with:

PreparedStmt.setLong(1, attributeID);

To insert a row where database generates a value for key, omit the primary key column in the sql and do not set its value in the prepared statement.