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Android学习笔记之SQLite数据库的使用及常用的增删改查方法、无sql语句的DRUD方法汇总

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（1）目录结构如下：

Android学习笔记之SQLite数据库的使用及常用的增删改查方法、无sql语句的DRUD方法汇总

（2）链接数据库的文件：DBHelper.java要继承SQLiteOpenHelper类

package com.lc.sqlite_demo1.db;

import android.content.Context;
import android.database.DatabaseErrorHandler;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class DBHelper extends SQLiteOpenHelper {

	private static final String DB_NAME = "mydb.db"; // 创建数据库的文件
	private static final int VERSION = 2; // 数据库版本,版本是更新的依据

	/*
	 * 需要这个构造方法: 数据库只有在调用getWritableDatabase();getReadableDatabase(;方法的时候才会创建数据库
	 */
	public DBHelper(Context context) {
		super(context, DB_NAME, null, VERSION);
	}

	/*
	 * public DBManager(Context context, String name, CursorFactory factory, int
	 * version) { super(context, name, factory, version); // TODO Auto-generated
	 * constructor stub
	 * 
	 * }
	 */

	/*
	 * 创建数据库的时候用到的语句
	 */
	@Override
	public void onCreate(SQLiteDatabase db) {
		// 数据类型：varchar、int、long、float、boolean、text、blob、clob等类型
		// 建表语句执行
		String sql = "create table person(pid integer primary key autoincrement,name varchar(64),address varchar(200))";
		db.execSQL(sql);
	}

	/*
	 * 更新数据库的时候使用到的; 这一句在一开始的时候是不会添加的，因为版本号是一样的只有执行一次之后，修改了版本号才会执行这段代码
	 */
	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		String sql = "alter table person add age integer";
		db.execSQL(sql);
	}

	@Override
	public void onOpen(SQLiteDatabase db) {
		super.onOpen(db);
	}

}

（3）创建一个DBManager.java还有数据的增、删、改、查及无sql语句的增、删、改、查方法汇总：

package com.lc.sqlite_demo1.db;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;

public class DBManager {

	private DBHelper dbHelper;
	private SQLiteDatabase database;

	public DBManager(Context context) {
		dbHelper = new DBHelper(context);
	}

	/*
	 * 用于更新数据的包括插入、删除、修改
	 */
	public boolean updateBySQL(String sql, Object[] bindArgs) {
		boolean flag = false;
		try {
			database.execSQL(sql, bindArgs);
			flag = true;
		} catch (SQLException e) {
			e.printStackTrace();
		} /*
		 * finally { if (database != null) { database.close(); } }
		 */
		return flag;
	}

	/*
	 * 单独一个方法，获得数据库的链接
	 */
	public void getDataBaseConn() {
		database = dbHelper.getWritableDatabase();
	}

	/*
	 * 释放数据库链接
	 */
	public void releaseConn() {
		if (database != null) {
			database.close();
		}
	}

	/*
	 * 查找数据的测试程序
	 */
	public void queryBySQL(String sql, String[] selectionArgs) {
		Cursor cursor = database.rawQuery(sql, selectionArgs);
		while (cursor.moveToNext()) {
			System.out.println("-->>"
					+ cursor.getString(cursor.getColumnIndex("name")));
			System.out.println("-->>"
					+ cursor.getString(cursor.getColumnIndex("address")));
			System.out.println("-->>"
					+ cursor.getInt(cursor.getColumnIndex("age")));
		}
	}

	/*
	 * 查找单条数据的查询方法
	 */
	public Map<String, String> querySingleResultBySQL(String sql,
			String[] selectionArgs) {
		Map<String, String> map = new HashMap<String, String>();
		Cursor cursor = database.rawQuery(sql, selectionArgs);
		int cols_len = cursor.getColumnCount();
		while (cursor.moveToNext()) {
			for (int i = 0; i < cols_len; i++) {
				String cols_name = cursor.getColumnName(i);
				String cols_value = cursor.getString(cursor
						.getColumnIndex(cols_name));
				if (cols_value == null) {
					cols_value = "";
				}
				map.put(cols_name, cols_value);
			}
		}
		return map;
	}

	/**
	 * 同构反射获得数据库的记录; 声明Class的属性必须都是String类型
	 * 
	 * @param sql
	 * @param selectionArgs
	 * @param cls
	 * @return
	 */
	public <T> T querySingleCursor(String sql, String[] selectionArgs,
			Class<T> cls) {
		T t = null;
		Cursor cursor = database.rawQuery(sql, selectionArgs);
		int cols_len = cursor.getColumnCount();
		while (cursor.moveToNext()) {
			try {
				t = cls.newInstance();
				for (int i = 0; i < cols_len; i++) {
					String cols_name = cursor.getColumnName(i);
					String cols_value = cursor.getString(cursor
							.getColumnIndex(cols_name));

					if (cols_value == null) {
						cols_value = "";
					}
					Field field = null;
					try {
						field = cls.getDeclaredField(cols_name);
					} catch (NoSuchFieldException e) {
						e.printStackTrace();
					}
					field.setAccessible(true);
					field.set(t, cols_value);
				}
			} catch (InstantiationException e) {
				e.printStackTrace();
			} catch (IllegalAccessException e) {
				e.printStackTrace();
			}

		}
		return t;
	}

	/**
	 * 同构反射获得多条数据库的记录; 声明Class的属性必须都是String类型
	 * 
	 * @param sql
	 * @param selectionArgs
	 * @param cls
	 * @return
	 */
	public <T> List<T> queryMutilCursor(String sql, String[] selectionArgs,
			Class<T> cls) {
		List<T> list = new ArrayList<T>();
		Cursor cursor = database.rawQuery(sql, selectionArgs);
		int cols_len = cursor.getColumnCount();
		while (cursor.moveToNext()) {
			try {
				T t = cls.newInstance();
				for (int i = 0; i < cols_len; i++) {
					String cols_name = cursor.getColumnName(i);
					String cols_value = cursor.getString(cursor
							.getColumnIndex(cols_name));

					if (cols_value == null) {
						cols_value = "";
					}
					Field field = null;
					try {
						field = cls.getDeclaredField(cols_name);
					} catch (NoSuchFieldException e) {
						e.printStackTrace();
					}
					field.setAccessible(true);
					field.set(t, cols_value);
					list.add(t);
				}
			} catch (InstantiationException e) {
				e.printStackTrace();
			} catch (IllegalAccessException e) {
				e.printStackTrace();
			}
		}
		return list;
	}

	/*
	 * 查找多条数据的查询方法
	 */
	public List<Map<String, String>> queryMutiResultBySQL(String sql,
			String[] selectionArgs) {
		List<Map<String, String>> list = new ArrayList<Map<String, String>>();
		Cursor cursor = database.rawQuery(sql, selectionArgs);
		int cols_len = cursor.getColumnCount();
		while (cursor.moveToNext()) {
			Map<String, String> map = new HashMap<String, String>();
			for (int i = 0; i < cols_len; i++) {
				String cols_name = cursor.getColumnName(i);
				String cols_value = cursor.getString(cursor
						.getColumnIndex(cols_name));
				if (cols_value == null) {
					cols_value = "";
				}
				map.put(cols_name, cols_value);
			}
			list.add(map);
		}
		return list;
	}

	public Cursor queryMutiCursor(String sql, String[] selectionArgs) {
		Cursor cursor = database.rawQuery(sql, selectionArgs);
		return cursor;
	}

	/**************************** 以下是不需要sql语句的查询方法 **********************************/

	/**
	 * 
	 * @param tabeName
	 * @param nullColumnHack
	 * @param values
	 * @return
	 */
	public boolean insertByNotSQL(String tabeName, String nullColumnHack,
			ContentValues values) {
		boolean flag = false;
		// insert into tableName(a,,b,c) values(?,?,?)
		long id = database.insert(tabeName, nullColumnHack, values);
		flag = (id > 0 ? true : false);
		return flag;
	}

	/**
	 * 无sql语句的更新操作
	 * 
	 * @param tabeName
	 * @param values
	 * @param whereClause
	 * @param whereArgs
	 * @return
	 */
	public boolean updateByNotSQL(String tabeName, ContentValues values,
			String whereClause, String[] whereArgs) {
		boolean flag = false;

		// update tableName set name =?,address=?,age=? where pid=?
		int count = database.update(tabeName, values, whereClause, whereArgs); // 影响数据的行数
		flag = (count > 0 ? true : false);

		return flag;
	}

	/**
	 * 无sql语句的删除操作
	 * 
	 * @param table
	 * @param whereClause
	 * @param whereArgs
	 * @return
	 */
	public boolean deleteNotSQL(String table, String whereClause,
			String[] whereArgs) {
		boolean flag = false;

		// delete from tableName where pid=?
		int count = database.delete(table, whereClause, whereArgs);
		flag = (count > 0 ? true : false);

		return flag;
	}

	/**
	 * sql标准写法：select [distinct][columnName] ... from tableName
	 * [where][selection][selectionArgs][groupBy][having][order by][limit]
	 * 
	 * @param distinct
	 * @param table
	 * @param columns
	 * @param selection
	 * @param selectionArgs
	 * @param groupBy
	 * @param having
	 * @param orderBy
	 * @param limit
	 * @return
	 */
	public Cursor queryByNotSQL(boolean distinct, String table,
			String[] columns, String selection, String[] selectionArgs,
			String groupBy, String having, String orderBy, String limit) {
		Cursor cursor = null;

		/*
		 * 这是一条折中 的查询方法，其他的方法就是一系列的构造函数
		 */
		cursor = database.query(distinct, table, columns, selection,
				selectionArgs, groupBy, having, orderBy, limit);

		return cursor;
	}
}

（4）测试类（要在清单文件中加权限！）

package com.lc.sqlite_demo1;

import java.util.List;
import java.util.Map;

import com.lc.sqlite_demo1.db.DBHelper;
import com.lc.sqlite_demo1.db.DBManager;

import android.content.ContentValues;
import android.database.Cursor;
import android.test.AndroidTestCase;

public class MyTest extends AndroidTestCase {
	/*
	 * 测试创建数据库，只有调用getReadableDatabase()/getReadableDatabase()方法才会创建数据库
	 */
	public void initTable() {
		DBHelper dbManager = new DBHelper(getContext());
		dbManager.getReadableDatabase();
	}

	public void insert() {
		// String sql = "insert into person(name,address,age) values(?,?,?)";
		String sql = "insert into person(name,address) values(?,?)";
		Object[] bindArgs = { "张三", "成都" };
		DBManager dbManager = new DBManager(getContext());
		dbManager.getDataBaseConn();
		dbManager.updateBySQL(sql, bindArgs);
		dbManager.releaseConn();
	}

	public void update() {
		String sql = "update person set name=?,address=?,age=? where pid =1";
		Object[] bindArgs = { "王五", "北京", 23 };
		DBManager dbManager = new DBManager(getContext());
		dbManager.getDataBaseConn();

		dbManager.updateBySQL(sql, bindArgs);
		dbManager.releaseConn();
	}

	public void delete() {
		String sql = "delete from person where pid =?";
		Object[] bindArgs = { 1 };
		DBManager dbManager = new DBManager(getContext());
		dbManager.getDataBaseConn();
		dbManager.updateBySQL(sql, bindArgs);
		dbManager.releaseConn();
	}

	public void query() {
		String sql = "select * from person";
		DBManager dbManager = new DBManager(getContext());
		dbManager.getDataBaseConn();
		dbManager.queryBySQL(sql, null);
		dbManager.releaseConn();
	}

	public void querySingleResultBySQLTest() {
		String sql = "select * from person where pid =?";
		DBManager dbManager = new DBManager(getContext());
		dbManager.getDataBaseConn();
		Map<String, String> map = dbManager.querySingleResultBySQL(sql,
				new String[] { "2" });
		System.out.println("--->>" + map.get("name"));
		System.out.println("--->>" + map.get("address"));
		System.out.println("--->>" + map.get("age"));
		dbManager.releaseConn();
	}

	public void queryMutiResultBySQLTest() {
		String sql = "select * from person where name like ?";
		DBManager dbManager = new DBManager(getContext());
		dbManager.getDataBaseConn();
		List<Map<String, String>> list = dbManager.queryMutiResultBySQL(sql,
				new String[] { "%张%" });
		for (Map<String, String> map2 : list) {
			System.out.println("---->>" + map2.get("name"));
			System.out.println("---->>" + map2.get("address"));
			System.out.println("--->>" + map2.get("age"));
		}
		dbManager.releaseConn();
	}

	/**************************** 以下是不需要sql语句的查询方法测试 **********************************/
	/*
	 * 无需查询语句的插入操作
	 */
	public void insertNotSQLTest() {
		DBManager dbManager = new DBManager(getContext());
		dbManager.getDataBaseConn();
		ContentValues values = new ContentValues();
		values.put("name", "xuliugen");
		values.put("address", "dfhkjsdhfkjhsd");
		values.put("age", 22);
		dbManager.insertByNotSQL("person", null, values);
		dbManager.releaseConn();
	}

	/*
	 * 无需查询语句的更新操作
	 */
	public void updateNotSQLTest() {
		DBManager dbManager = new DBManager(getContext());
		dbManager.getDataBaseConn();
		ContentValues values = new ContentValues();
		values.put("name", "fff");
		values.put("address", "12srqrqwrewrqrwetrew");
		values.put("age", 22);

		dbManager.updateByNotSQL("person", values, "pid=? and name=?",
				new String[] { "5", "fff" });
		dbManager.releaseConn();
	}

	/*
	 * 无需查询语句的删除操作
	 */
	public void deleteNotSQL() {
		DBManager dbManager = new DBManager(getContext());
		dbManager.getDataBaseConn();
		dbManager.deleteNotSQL("person", "pid=?", new String[] { "5" });
		dbManager.releaseConn();
	}

	/*
	 * 无需查询语句的查询操作
	 */
	public void queryByNotSQLTest() {
		DBManager dbManager = new DBManager(getContext());
		dbManager.getDataBaseConn();
		Cursor cursor = dbManager.queryByNotSQL(false, "person", null, null,
				null, null, null, null, null);
		while (cursor.moveToNext()) {
			System.out.println("-->>" + cursor.getColumnIndex("name"));
			System.out.println("-->>" + cursor.getColumnIndex("age"));
			System.out.println("-->>" + cursor.getColumnIndex("address"));
		}
		dbManager.releaseConn();
	}
}

其他文件不做修改！可以实现数据的增删改查等操作！


本文标题：Android学习笔记之SQLite数据库的使用及常用的增删改查方法、无sql语句的DRUD方法汇总
本文链接：https://blog.quwenai.cn/post/3689.html
作者授权：除特别说明外，本文由 toobug 原创编译并授权 TOOBUG信息安全网 刊载发布。
版权声明：本文不使用任何协议授权，您可以任何形式自由转载或使用。

本文链接：https://blog.quwenai.cn/post/3689.html 

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