I want to insert multiple rows into a MySQL table at once using Java. The number of rows is dynamic. In the past I was doing...
for (String element : array) {
myStatement.setString(1, element[0]);
myStatement.setString(2, element[1]);
myStatement.executeUpdate();
}
I'd like to optimize this to use the MySQL-supported syntax:
INSERT INTO table (col1, col2) VALUES ('val1', 'val2'), ('val1', 'val2')[, ...]
but with a PreparedStatement
I don't know of any way to do this since I don't know beforehand how many elements array
will contain. If it's not possible with a PreparedStatement
, how else can I do it (and still escape the values in the array)?
You can create a batch by PreparedStatement#addBatch()
and execute it by PreparedStatement#executeBatch()
.
Here's a kickoff example:
public void save(List<Entity> entities) throws SQLException {
try (
Connection connection = database.getConnection();
PreparedStatement statement = connection.prepareStatement(SQL_INSERT);
) {
int i = 0;
for (Entity entity : entities) {
statement.setString(1, entity.getSomeProperty());
// ...
statement.addBatch();
i++;
if (i % 1000 == 0 || i == entities.size()) {
statement.executeBatch(); // Execute every 1000 items.
}
}
}
}
It's executed every 1000 items because some JDBC drivers and/or DBs may have a limitation on batch length.
See also: