jdbc batch different statements - mysql

Question

Now I've been searching this all over, i get the same answer. What I want is to have different statements batched under one variable using jdbc in java. So far what I get is batching statements that have the same pattern, e.g, INSERT INTO table VALUES('?','?'). This can be done using a preparedstatement. But I have tried to batch different types of statements using java.sql.Statement and they executed well. for example an update and an insert under one statement, commit once. But now the problem with java.sql.Statement is that it does now do what preparedStatement does, what people call escaping. Again the problem with preparedStatement is it only batches statements of the same pattern, as in, you can't update and insert. it has to be one of the two.
So now I thought I would use java.sql.Statement, but is there a library that does what preparedStatement does,String escaping to avoid Sql injection. Also, if I am mistakening batching with another terminology that I may not know, rather correct me and tell me what I am wanting to do is called, that is, to execute multiple different statements under one java.sql.Statement.
One last thing, when batching i realized there is no validation of syntax, which I wouldn't want, all errors are checked during executing, this might also fall under a library that can validate Sql.

Answer 1

Whatever you have mentioned is correct.
You can batch similar set of statements and can get executed at once. But as far as my knowledge there is no library in java which groups or batches different kinds of statements together and gets executed.
The last thing I want to tell is that the sql statement will be compiled only once when you are using the PreparedStatement object, if any errors in the sql statement, will be thrown, otherwise the statement will gets executed. If the same statement is sent to the database again with different values, the statement will not be compiled and simply executed by the database server.

Answer 2

Since you're looking for a library to do this kind of thing, yes, jOOQ can do it for you via its BatchedConnection, and you don't even have to use jOOQ's DSL to access this feature, though it works with the DSL as well. The following code snippet illustrates how this works.
Let's assume you have this logic:
// This is your original JDBC connection
try (Connection connection = ds.getConnection()) {
doSomethingWith(connection);
}
// And then:
void doSomethingWith(Connection c) {
try (PreparedStatement s = c.prepareStatement("INSERT INTO t (a, b) VALUES (?, ?)")) {
s.setInt(1, 1);
s.setInt(1, 2);
s.executeUpdate();
}
try (PreparedStatement s = c.prepareStatement("INSERT INTO t (a, b) VALUES (?, ?)")) {
s.setInt(1, 3);
s.setInt(1, 4);
s.executeUpdate();
}
try (PreparedStatement s = c.prepareStatement("INSERT INTO u (x) VALUES (?)")) {
s.setInt(1, 1);
s.executeUpdate();
}
try (PreparedStatement s = c.prepareStatement("INSERT INTO u (x) VALUES (?)")) {
s.setInt(1, 2);
s.executeUpdate();
}
}
Now, instead of re-writing your code, you can simply wrap it with jOOQ glue code:
// This is your original JDBC connection
try (Connection connection = ds.getConnection()) {
// Now wrap that with jOOQ and turn it into a "BatchedConnection":
DSL.using(connection).batched(c -> {
// Retrieve the augmented connection again from jOOQ and run your original logic:
c.dsl().connection(connection2 -> {
doSomethingWith(connection2);
});
});
}
Now, whatever your method doSomethingWith() is doing with a JDBC Connection, it is now getting batched as good as possible, i.e. the first two inserts are batched together, and so are the third and fourth one.