Android使用SQLite的代码示例
时间: 2023-12-27 18:10:09 浏览: 78
以下是使用SQLite的代码示例,包括创建数据库、创建表、插入数据、查询数据和关闭数据库等操作。
1. 创建数据库
```java
public class MyDatabaseHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "my_database.db";
private static final int DB_VERSION = 1;
public MyDatabaseHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
// 创建表
String createTableSql = "CREATE TABLE IF NOT EXISTS user ("
+ "_id INTEGER PRIMARY KEY AUTOINCREMENT,"
+ "name TEXT,"
+ "age INTEGER)";
db.execSQL(createTableSql);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// 升级数据库
db.execSQL("DROP TABLE IF EXISTS user");
onCreate(db);
}
}
```
2. 插入数据
```java
MyDatabaseHelper dbHelper = new MyDatabaseHelper(this);
SQLiteDatabase db = dbHelper.getWritableDatabase();
// 插入数据
ContentValues values = new ContentValues();
values.put("name", "Tom");
values.put("age", 20);
db.insert("user", null, values);
db.close();
```
3. 查询数据
```java
MyDatabaseHelper dbHelper = new MyDatabaseHelper(this);
SQLiteDatabase db = dbHelper.getReadableDatabase();
// 查询数据
Cursor cursor = db.query("user", null, null, null, null, null, null);
while (cursor.moveToNext()) {
int id = cursor.getInt(cursor.getColumnIndex("_id"));
String name = cursor.getString(cursor.getColumnIndex("name"));
int age = cursor.getInt(cursor.getColumnIndex("age"));
Log.d("MainActivity", "id: " + id + ", name: " + name + ", age: " + age);
}
cursor.close();
db.close();
```
4. 关闭数据库
```java
db.close();
```
以上示例仅供参考,实际使用时需要根据具体的业务需求进行修改和完善。