SQLitedatabase之SQLiteOpenHelper進行CRUD

衆所周知，Android開發中使用數據庫Sqlite. 這裏簡單記錄一下SQLite的使用。

這裏按CRUD順序進行簡單記錄下：

直接貼操作代碼，文字敘述沒什麼用！^_^

首先是DatabaseHelper

public class DatabaseHelper extends SQLiteOpenHelper {
    private static final int DB_VERSION = 7;//數據庫版本，進行手動更新
    private static final String DB_NAME = "SQLiteTest.db";
    private static final String TAG = "DatabaseHelper.class";
    private static final String SQLITETABLE = "sqliteTable";
    private static final String AGE = "age";
    private static final String NAME = "name";

    public DatabaseHelper(Context context) {
        this(context, DB_NAME, DB_VERSION);
    }

    public DatabaseHelper(Context context, int version) {
        this(context, DB_NAME, version);
    }

    public DatabaseHelper(Context context, String name, int version) {
        this(context, name, null, version);
    }

    public DatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
        super(context, name, factory, version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

        String sql = "create table if not exists " + SQLITETABLE + "(id INTEGER primary key autoincrement," + NAME + " TEXT," + AGE + " TEXT)";
        db.execSQL(sql);
        Log.d(TAG, "onCreate: create database");
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("drop table if exists sqliteTable");
        onCreate(db);
        Log.d(TAG, "upgrade database");
    }
}

Create

我這裏將所有方法寫到DatabaseDao類裏面

   public DatabaseDao(Context context) {
        databaseHelper = new DatabaseHelper(context);
    }

在需要調用的類中直接new DatabaseDao(this)即可初始化創建數據庫表

Insert

    public void insert(String x, String age) {
        String sql = "insert into " + SQLITETABLE + "(name,age) values(?,?)";
        sqLiteDatabase = databaseHelper.getWritableDatabase();
//        String x = "x";
        sqLiteDatabase.execSQL(sql, new String[]{x, age});
    }

總結：insert into tableName(column1,column2...) values(?,?...)

Retrieve

        dataBeans.clear();
        String s = "select * from " + SQLITETABLE + " where name =?";
        sqLiteDatabase = databaseHelper.getWritableDatabase();
        Cursor cursor = sqLiteDatabase.rawQuery(s, new String[]{name});
        if (cursor.moveToFirst()) {
            while (cursor.moveToNext()) {
                String name1 = cursor.getString(cursor.getColumnIndex("name"));
                String age1 = cursor.getString(cursor.getColumnIndex("age"));
                Log.d(TAG, "retrieveName: name=" + name1 + ",age=" + age1);
                DataBean dataBean = new DataBean();
                dataBean.setName(name1);
                dataBean.setAge(age1);
                dataBeans.add(dataBean);
            }
        }
        return dataBeans;
    }

    public List<DataBean> retrieveAge(List<DataBean> dataBeans, String age) {
        String sql = "select * from " + SQLITETABLE + " where age=?";
        sqLiteDatabase = databaseHelper.getWritableDatabase();
        Cursor cursor = sqLiteDatabase.rawQuery(sql, new String[]{age});
        if (cursor.moveToFirst()) {
            while (cursor.moveToNext()) {
                String name1 = cursor.getString(cursor.getColumnIndex("name"));
                String age1 = cursor.getString(cursor.getColumnIndex("age"));
                Log.d(TAG, "retrieveAge: name=" + name1 + ",age=" + age1);
                DataBean dataBean = new DataBean();
                dataBean.setName(name1);
                dataBean.setAge(age1);
                dataBeans.add(dataBean);
            }
        }
        return dataBeans;

總結：select * from tableName where column=?


通過SQL語句篩選，通過sqliteDatabase進行rawQuery進行相應查詢


sqLiteDatabase.rawQuery(sql, new String[]{age});

    public void updateName(String age, String newName) {
        String sql = "update sqliteTable set name='" + newName + "' where age='" + age + "'";
        sqLiteDatabase = databaseHelper.getWritableDatabase();
        sqLiteDatabase.execSQL(sql);
    }

總結：update tableName set column = ‘x’ where column2='y'

需要指出的是，我在使用這個語句的時候需要加‘’才成功，不然會報錯。

Delete

   public void deleteName(String name) {
        String sql = "delete from " + SQLITETABLE + " where name='" + name + "'";
        sqLiteDatabase = databaseHelper.getWritableDatabase();
        sqLiteDatabase.execSQL(sql);
    }

    public void deleteAge(String age) {
        String sql = "delete from " + SQLITETABLE + " where age=" + age + "";
        sqLiteDatabase = databaseHelper.getWritableDatabase();
        sqLiteDatabase.execSQL(sql);
    }

總結：delete from tableName where column='x'
需要指出的是，我在使用這個語句的時候需要加‘’才成功，不然會報錯。

結語，這篇文章沒什麼東西，都是通過簡單的SQL語句實現，當然對於insert,update等也可以通過ContentValues來實現，我這裏沒那樣寫。
關於greenDao的使用請參考 SQLitedatabase之GreenDao進行CRUD

源碼下載：
CSDN
gihtub