adityaashinde / flutter-SQFLite

a basic flutter examples using SQFLite

flutter-SQFLite

a basic flutter examples using SQFLite

SQFLite :

• Sqflite is a package in flutter that is used for implementing SQLite databases in flutter.

• If a large amount of data is to be stored locally i.e. on the mobile phone then we can use SQLite database.

• Databases provides faster inserts, updates and queries than otherr local solutions (i.e. shared preferences).

• To use the SQLite database we have sqflite package.

• To perform operations database we need first to open the database i.e. establish a connection with the database.

1). openDatabase():

• The openDatabase method from the SQFLite package is called to open the database. An SQLite database is a file in the syatem identified by a path. If relatives, this path is relative to the path obtained by getDatabasesPath(), which is the default database directly on Android and the documents directory on iOS/MacOS.

    ```
    Future<sql.Database> opendb() async {
        return await sql.openDatabase(
            "todo1.db",
            version : 1,
            onCreate : (db, version) async {
                await createtable(db);
            }
        )
    }
    ```
  

• The openDatabase method contains the following optional paramaters :

    ```
    Future<Database> openDatabase(String path,
    {
        int? version,
        OnDatabaseConfigureFn? onConfigure,
        OnDatabaseCreateFn? onCreate,
        OnDatabaseVersionChangeFn? onUpgrade,
        OnDatabaseVersion?ChangeFn? onDowngrade,
        OnDatabaseOpenFn? onOpen,
        bool? readOnly = false,
        bool? singleInstance = true
    })
    ```
  

  • 1. The onCreate method is called if the database does not exist.
  • 2. onUpgarde method is called if the onCreate method is not specified. If the database already exists and [version] is higher than the last database version.
  • 3. onDowngrade method is called if the version is lower than the previous version
  • 4. onOpen method is called after the database version has been set and before openDatabase returns. singleInstance is a boolean flag that is true by default and returns a single instance of the database.

2). Create a table in the Database

• To store the data in the database we must create tables.

• To create a table in the database we can call the execute method and specify the query to crate the table.

  Future<void> createtable(sql.Database db) async {
      await db.database.execute(
  
          """  CREATE TABLE IF NOT EXISTS todoTasks1( id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
              title TEXT,
              description TEXT,
              date TEXT,
              done INT ) """,
      );
  }