批处理模式下的 Select JDBC SQL

Question

Why is there no batchSelect in JDBC?

Is there some good way to handle select for multiple keys or ids?

Creating a query matching the length of all possible keys seem silly, because the database couldn't reuse prepared statements. Using stored procedures is very database dependant.

Are their any better ways?

Answer 1

Use the IN clause. Eg

SELECT 
    id, name, value 
FROM 
    entity
WHERE 
    id IN (1, 13, 42)

This returns the entities having an id of 1 , 13 and 42 in a ResultSet with 3 rows.

Using the IN clause in a JDBC PreparedStatement is however not exactly trivial. As to how to do this, check this question: What is the best approach using JDBC for parameterizing an IN clause?