Ionic 3 SQLite - database as private member variable vs. creating a new database on every query?

Question

I have a simple question - would it be better in Ionic 3 to have the opened database in a private member variable of a database provider class, or to call create every time the database is queried?

I.e. this...

private db: SQLiteObject;

constructor() {
  this.sqlite.create(...)
  .then((db: SQLiteObject) => {
    this.db = db;
  })
}

queryMethod() {
  db.executeSql(sql, {});
}

...or this?

constructor() {

}

queryMethod() {
  this.sqlite.create(...)
  .then((db: SQLiteObject) => {
    db.executeSql(sql, {});
  });
}

I do see a problem with the first approach, as there's a small probability that the database might not have been created before it's accessed.

Answer 1

Yes, Since this is Promise you always need to use the 2nd option.Then you will not have any issues. That means you need to execute the query after resolving the promise.

Follow below pattern always:

queryMethod() {
  this.sqlite.create(...)
  .then((db: SQLiteObject) => {
    db.executeSql(sql, {});
  });
}