01 - Queries

When we previously used the Sequelize findall() method, we just took it for granted that it would work. But what exactly is going on underneath? Let's take a closer look.

findall()

Here is one of our methods from the authtestcontroller file:

AuthTestModel
        .findAll({
            where: { owner: userid }
        })

We know that it is going to attempt to find a user in the AuthTest table where the values for the id and owner columns match the supplied values. When called, this method runs the following SQL statement: SELECT * FROM AuthTest WHERE owner = userid;. In other words: SELECT everything FROM the AuthTest table WHERE the owner column matches our value of userid. You can see from our code which parts of the code correspond to each part of the statement.

Of course, this isn't the only method we used which runs a SQL statement. While findAll and findOne run SELECT statements, we also use the create method to add data to the table, which runs a CREATE statement. The following table shows some of the standard Sequelize query methods and the different SQL statements that they represent:

Sequelize Method	SQL Statement
findAll()	SELECT...
findOne()	SELECT... LIMIT 1
create()	INSERT...
update()	UPDATE...
destroy()	DELETE
createTable()	CREATE TABLE...
dropTable()	DROP TABLE...

There are many different ways to adjust or enhance your queries, primarily using Operators. To learn more about this and other topics relating to queries, check the Sequelize docs here.