android Sqlite基本操作

　　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;    }
  
  }

原文地址：https://www.cnblogs.com/endian11/p/9540755.html