How to connect to specific database using JDBC and Google Apps Script - mysql

Question

I'm trying to connect to a Google Cloud MySQL 5.7 instance using GAS and JDBC. I'm able to run the following without error:
var conn = Jdbc.getCloudSqlConnection("jdbc:google:mysql://my-instance-111111:us-central1:mydbname", user,userPwd)
But this doesn't connect to a specific database, i.e. when I run
var stmt = conn.createStatement();
var results = stmt.executeQuery('SELECT col FROM myTable;');
I get Error Exception: No database selected.
One approach to try to fix:
The GAS docs indicate that I can use advanced parameters to include the DB name, but when I run var conn = Jdbc.getCloudSqlConnection("jdbc:google:mysql://my-instance-111111:us-central1:mydbname", user,userPwd,mydbname) ,
I get Exception: The parameters (String,String,String,String) don't match the method signature for Jdbc.getCloudSqlConnection.
A collection of getCloudSqlConnection statements that I've tried based on a number of StackOverflow posts:
var conn = Jdbc.getCloudSqlConnection("jdbc:google:mysql://my-instance-111111:us-central1:mydbname/mydbname", user,userPwd)
var conn = Jdbc.getCloudSqlConnection("jdbc:google:mysql://my-instance-111111:us-central1:mydbname:3306/mydbname", user,userPwd)
var conn = Jdbc.getCloudSqlConnection("jdbc:google:mysql://my-instance-111111:us-central1:mydbname:3307/mydbname", user,userPwd)
For the above statements, I also tried replacing my-instance-111111:us-central1:mydbname with the public IP supplied on the GC overview webpage. All return Exception: Failed to establish a database connection. Check connection string, username and password.
I'm using user root and the appropriate password. I can enter the DB via the command line with the user and password that I'm supplying in GAS, so I don't think I'm supplying the wrong user and password.
Edit:
I went back to the docs like #AddonDepot mentioned and realized that I need to pass an object, but I still can't get this work....
var obj = {
connectTimeoutSeconds: 15,
database: "mydbname",
instance: "my-instance-111111:us-central1:mydbname",
password: userPwd,
queryTimeoutSeconds: 15,
user: user };
var conn = Jdbc.getCloudSqlConnection("jdbc:google:mysql://my-instance-111111:us-central1:mydbname", obj);
returns
Exception: The following connection properties are unsupported: database,instance,connectTimeoutSeconds,queryTimeoutSeconds. .
Did I do something wrong in creating the object? I'm guessing not, because GAS recognizes user and password. Why wouldn't it recognize the other advanced parameters?

Answer 1

We have to distinguish between database system instances (sometimes referred simply as database; I'll use instances) and databases within them. That means that you may have an instance but may not have created any database in it.
You can use Apps Script to create a new database in your instance:
const connectionName = 'connection-name:for-your:instance'
const dbName = 'database'
const username = 'user'
const password = 'password'
function createDB() {
const conn = Jdbc.getCloudSqlConnection(`jdbc:google:mysql://${connectionName}`, username, password)
conn.createStatement().execute('CREATE DATABASE ' + dbName)
}
Once you have the database created in your instance you can use it:
function useDB() {
const conn = Jdbc.getCloudSqlConnection(`jdbc:google:mysql://${connectionName}/${dbName}`, username, password)
// Use conn
}
References
JDBC (Google Apps Script guide)