android Sqlite基本操作

Posted 2021-01-01 endian11

　　新建一个类(ex:UserDBHelper)继承SQLiteOpenHelper

• 构造函数里面建数据库

    public UserDBHelper(Context context, int version) {
          super(context, DB_NAME,null,version);
      }
  

• onCreate方法里面建表

     /**
       * 只在数据库生成的时候调用，一般我们会在
       * 这个方法里建表
       * @param sqLiteDatabase
       */
      @Override
      public void onCreate(SQLiteDatabase sqLiteDatabase) {
          Log.d(TAG, "onCreate: ");
          String drop_table = "DROP TABLE IF EXISTS " + TABLE_NAME + ";";
          Log.d(TAG, "onCreate: drop_table_sql "+ drop_table);
          sqLiteDatabase.execSQL(drop_table);
  
          String create_sql = "CREATE TABLE IF NOT EXISTS "+ TABLE_NAME + " (" +
                  "_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL," +
                  "name VARCHAR NOT NULL," + "age INTEGER NOT NULL," +
                  "height LONG NOT NULL," + "weight FLOAT NOT NULL," +
                  "married INTEGER NOT NULL," + "update_time VARCHAR NOT NULL" +
                   ",phone VARCHAR ,password VARCHAR"+
                  ");";
          Log.d(TAG, "crate_table sql: "+create_sql);
          sqLiteDatabase.execSQL(create_sql);
      }
  

• onUpgrade方法里面是升级数据库表

  @Override
      public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
          Log.d(TAG, "onUpgrade: oldVersion="+oldVersion+" newVersion:"+newVersion);
          if (newVersion > 1){
              String alertSql = "ALTER TABLE " + TABLE_NAME + " ADD COLUMN phone VARCHAR;";
              Log.d(TAG, "onUpgrade: alertSQL="+alertSql);
              sqLiteDatabase.execSQL(alertSql);
              alertSql = "ALTER TABLE " + TABLE_NAME + " ADD COLUMN password VARCHAR;";
              Log.d(TAG, "onUpgrade: alertSQL="+alertSql);
              sqLiteDatabase.execSQL(alertSql);
  
          }
  
      }
  
  
  

  package com.safeluck.floatwindow.db;
  
  import android.content.ContentValues;
  import android.content.Context;
  import android.database.sqlite.SQLiteDatabase;
  import android.database.sqlite.SQLiteOpenHelper;
  import android.util.Log;
  
  import java.util.List;
  
  /**
   * aaa
   * Created by lzw on 2018/8/23. 15:28:33
   * 邮箱：[email protected]
   * All Rights Saved! Chongqing AnYun Tech co. LTD
   */
  public class UserDBHelper extends SQLiteOpenHelper {
      private static final String DB_NAME = "userDB";
      private static final int DB_VERSION = 1;
      private static  UserDBHelper mHelper ;
      private static final String TABLE_NAME = "user";
      private static final String TAG = "UserDbHelper";
      private SQLiteDatabase DB = null;
      public UserDBHelper(Context context, int version) {
          super(context, DB_NAME,null,version);
      }
  
      public static UserDBHelper getInstance(Context context,int version){
          if (version>0 && mHelper == null){
              mHelper = new UserDBHelper(context,version);
          }else if (mHelper == null){
              mHelper = new UserDBHelper(context,DB_VERSION);
          }
          return mHelper;
      }
  
  
      /**
       * 获取只读的数据库
       * @return
       */
      public SQLiteDatabase getReadLink() {
          DB = mHelper.getReadableDatabase();
          return DB;
      }
  
      public SQLiteDatabase getWriteDB() {
          DB = mHelper.getWritableDatabase();
          return DB;
      }
  
      /**
       * 只在数据库生成的时候调用，一般我们会在
       * 这个方法里建表
       * @param sqLiteDatabase
       */
      @Override
      public void onCreate(SQLiteDatabase sqLiteDatabase) {
          Log.d(TAG, "onCreate: ");
          String drop_table = "DROP TABLE IF EXISTS " + TABLE_NAME + ";";
          Log.d(TAG, "onCreate: drop_table_sql "+ drop_table);
          sqLiteDatabase.execSQL(drop_table);
  
          String create_sql = "CREATE TABLE IF NOT EXISTS "+ TABLE_NAME + " (" +
                  "_id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL," +
                  "name VARCHAR NOT NULL," + "age INTEGER NOT NULL," +
                  "height LONG NOT NULL," + "weight FLOAT NOT NULL," +
                  "married INTEGER NOT NULL," + "update_time VARCHAR NOT NULL" +
                   ",phone VARCHAR ,password VARCHAR"+
                  ");";
          Log.d(TAG, "crate_table sql: "+create_sql);
          sqLiteDatabase.execSQL(create_sql);
      }
  
      @Override
      public void onUpgrade(SQLiteDatabase sqLiteDatabase, int oldVersion, int newVersion) {
          Log.d(TAG, "onUpgrade: oldVersion="+oldVersion+" newVersion:"+newVersion);
          if (newVersion > 1){
              String alertSql = "ALTER TABLE " + TABLE_NAME + " ADD COLUMN phone VARCHAR;";
              Log.d(TAG, "onUpgrade: alertSQL="+alertSql);
              sqLiteDatabase.execSQL(alertSql);
              alertSql = "ALTER TABLE " + TABLE_NAME + " ADD COLUMN password VARCHAR;";
              Log.d(TAG, "onUpgrade: alertSQL="+alertSql);
              sqLiteDatabase.execSQL(alertSql);
  
          }
  
      }
  
      /**
       * 删除一行数据
       * @param condition
       */
      public void deleteRow(String condition){
          DB.delete(TABLE_NAME,condition,null);
      }
  
  
      public long addUser(List<UserInfo> userInfos){
          long reuslt = -1;
          for (int i = 0; i < userInfos.size(); i++) {
              UserInfo info = userInfos.get(i);
              ContentValues cv = new ContentValues();
              cv.put("name", info.name);
              cv.put("age", info.age);
              cv.put("height", info.height);
              cv.put("weight", info.weight);
              cv.put("married", info.married);
              cv.put("update_time", info.update_time);
              cv.put("phone", info.phone);
              cv.put("password", info.password);
              reuslt = DB.insert(TABLE_NAME,"",cv);
          }
          Log.d(TAG, "addUser: result="+reuslt);
          return reuslt;
      }
  
  }