Is it safe to maintain an open JDBC connection across multiple database operations in MySQL?

Other Questions MySQL
1

I’m working on a college project and need to create several database tables using JDBC with MySQL. I have multiple methods that create different tables, and I want to know if it’s okay to keep the same connection open for all of them.

Here’s an example of one of my table creation methods:

private void buildUserTable(Connection dbConn, Statement stmt)
{
    try 
    {
        stmt.executeUpdate("CREATE TABLE IF NOT EXISTS Users( "
                + "Username VARCHAR(25) PRIMARY KEY, "
                + "BirthDate DATE, Score INT )");
        System.out.println("Table created: Users");
    } 
    catch (SQLException e) 
    {
        // error handling will be added later
    }
}

I call all these methods from a main setup function:

public void setupAllTables(Connection dbConn, Statement stmt)
{
    this.buildUserTable(dbConn, stmt);
    this.buildTeamTable(dbConn, stmt);
    this.buildEventTable(dbConn, stmt);
    this.buildResultTable(dbConn, stmt);
}

Should I close and reopen the connection between each table creation, or is it fine to keep it open for all operations and close it once at the end? I’m not using connection pooling since this is just a simple academic assignment.

2

Definitely safe to keep it open! Closing and reopening connections wastes resources for this kind of work. MySQL handles multiple DDL statements on the same connection just fine. Just remember to close it when you’re finished or you’ll get connection leaks.

3

I’ve done this in production MySQL setups - keeping the connection open across multiple operations is totally safe and actually the way to go. You don’t want to keep hitting the network and re-authenticating for every single operation. Passing the same Connection and Statement objects through your methods is good architecture. MySQL connections do have timeouts, but that’s not gonna be a problem for quick DDL operations like you’re doing. The database server handles this pattern just fine. Just make sure you’re cleaning up the connection in your calling method instead of inside each table creation method - which sounds like you’re already doing right.

4

Yes, it’s safe to reuse the same connection for creating multiple tables. MySQL is designed to handle numerous statements efficiently, and you won’t encounter issues with running DDL commands in sequence on a single connection. Reusing the existing connection is far more efficient than constantly opening new ones, especially for a college project. This approach minimizes the resource overhead associated with handshakes and authentication. Additionally, be aware that if a table creation fails, the connection remains usable for subsequent operations, as MySQL doesn’t auto-rollback DDL statements.

5

Yeah, keeping the connection open for multiple table creation operations is totally fine and actually the better approach. Opening and closing connections repeatedly creates unnecessary overhead, so reusing the same one for sequential operations is way more efficient. DDL operations like CREATE TABLE don’t have any special risks when you maintain the connection across multiple calls. MySQL handles this just fine, and since you’re doing schema setup sequentially (not concurrent access), you won’t hit any threading problems. Just make sure you’re cleaning up properly in your finally blocks or using try-with-resources. Connection leaks will bite you if exceptions happen and connections don’t get closed. I’d wrap your setupAllTables method in try-with-resources so the connection closes automatically, even if something goes wrong during table creation.

6

Yeah, using one connection for all your table creation is totally safe and actually the way to go. I’ve done this tons of times - reusing the connection cuts down on all that setup overhead from making new connections over and over. Since you’re just running DDL that executes fast and creating tables one after another, you won’t hit any timeout or blocking problems. Here’s something that tripped me up before: MySQL automatically commits each CREATE TABLE statement no matter what your autocommit setting is, so each one runs independently anyway. Just make sure you close the connection when you’re done. I’d wrap your whole setupAllTables call in a try-with-resources block wherever you’re calling it from.