问题
My current method is this:
SELECT TOP 1 ID FROM DATAENTRY ORDER BY ID DESC
This assumes the latest inserted item always has the highest unique ID (primary key, autoincrementing). Something smells wrong here.
Alternatives?
回答1:
If the JDBC driver supports it, you can also just use Statement#getGeneratedKeys() for that.
String sql = "INSERT INTO tbl (col) VALUES (?)";
preparedStatement = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
preparedStatement.setString(1, col);
preparedStatement.executeUpdate();
generatedKeys = preparedStatement.getGeneratedKeys();
if (generatedKeys.next()) {
long id = generatedKeys.getLong(1);
} else {
// Throw exception?
}
回答2:
If using MySQL you can do
select last_insert_id();
If using MS SQL
select scope_identity();
For H2, I believe it's
CALL SCOPE_IDENTITY();
but I don't have any experience with that DB
来源：https://stackoverflow.com/questions/2647407/sql-java-h2-whats-the-best-way-to-retrieve-the-unique-id-of-the-single-item