GreenDao 数据库升级

1APP开发期间的数据库改动（APP未上线）

直接上DaoMaster的代码

/** * WARNING: Drops all table on Upgrade! Use only during development. */
public static class DevOpenHelper extends OpenHelper {    
  public DevOpenHelper(Context context, String name, CursorFactory factory) {
             super(context, name, factory);    
  }    
  @Override    
  public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {            
        Log.i("greenDAO", "Upgrading schema from version " + oldVersion + " to " + newVersion + " by dropping all tables");        
        dropAllTables(db, true);        
        onCreate(db);    
  }
}

注意看第一行注释：WARNING: Drops all table on Upgrade! Use only during development.

数据库升级的话，会删除所有表,然后重新创建。这种方式在开发期间，APP还没有上线之前是可以的。

当APP上线后，我们不能使用这种方式，因为这样会导致已经存在的数据会被删除。

2APP上线后,数据库升级

需要我们写一个类来实现OpenHelper

1. 我们自己实现了onUpgrade方法来自定义升级过程。

        2.当然升级过程中也要修改DaoMaster.SCHEMA_VERSION

        3.当DaoMaster.SCHEMA_VERSION 跟你当前数据库的版本比较后,

        会根据你当前数据库的版本，然后进行升级。

       4.关键代码onUpgrade方法,会比较新数据库和旧数据库的版本,然后执行相应的sql升级：

  SQLiteOpenHelper.java

克隆地址 一键复制 原始数据 历史

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       /** 

      
      
      
      
      
      
      
      

       
       
       
        * Created by weijianxing on 9/22/15. 

      
      
      
      
      
      
      
      

       
       
       
        */

      
      
      
      
      
      
      
      

       
       
       
       public 
       
       
       
       class 
       
       
       
       SQLiteOpenHelper 
       
       
       
       extends 
       
       
       
       DaoMaster
       
       
       
       .
       
       
       
       OpenHelper 
       
       
       
       {

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      
    
       
       
       
       private 
       
       
       
       static 
       
       
       
       final 
       
       
       
       String 
       
       
       
       DB_NAME 
       
       
       
       = 
       
       
       
       "test.db"
       
       
       
       ;

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      
    
       
       
       
       private 
       
       
       
       static 
       
       
       
       final 
       
       
       
       SortedMap
       
       
       
       <
       
       
       
       Integer
       
       
       
       , 
       
       
       
       Migration
       
       
       
       > 
       
       
       
       ALL_MIGRATIONS 
       
       
       
       = 
       
       
       
       new 
       
       
       
       TreeMap
       
       
       
       <>();

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      
    
       
       
       
       static 
       
       
       
       {

      
      
      
      
      
      
      
      
        
       
       
       
       ALL_MIGRATIONS
       
       
       
       .
       
       
       
       put
       
       
       
       (
       
       
       
       1
       
       
       
       , 
       
       
       
       new 
       
       
       
       V1Migration
       
       
       
       ());

      
      
      
      
      
      
      
      
        
       
       
       
       ALL_MIGRATIONS
       
       
       
       .
       
       
       
       put
       
       
       
       (
       
       
       
       2
       
       
       
       , 
       
       
       
       new 
       
       
       
       V2Migration
       
       
       
       ());

      
      
      
      
      
      
      
      
        
       
       
       
       ALL_MIGRATIONS
       
       
       
       .
       
       
       
       put
       
       
       
       (
       
       
       
       3
       
       
       
       , 
       
       
       
       new 
       
       
       
       V3Migration
       
       
       
       ());

      
      
      
      
      
      
      
      
    
       
       
       
       }

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      
    
       
       
       
       public 
       
       
       
       SQLiteOpenHelper
       
       
       
       (
       
       
       
       Context 
       
       
       
       context
       
       
       
       , 
       
       
       
       SQLiteDatabase
       
       
       
       .
       
       
       
       CursorFactory 
       
       
       
       factory
       
       
       
       ) 
       
       
       
       {

      
      
      
      
      
      
      
      
        
       
       
       
       super
       
       
       
       (
       
       
       
       context
       
       
       
       , 
       
       
       
       DB_NAME
       
       
       
       , 
       
       
       
       factory
       
       
       
       );

      
      
      
      
      
      
      
      
    
       
       
       
       }

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      
    
       
       
       
       @Override

      
      
      
      
      
      
      
      
    
       
       
       
       public 
       
       
       
       void 
       
       
       
       onCreate
       
       
       
       (
       
       
       
       SQLiteDatabase 
       
       
       
       db
       
       
       
       ) 
       
       
       
       {

      
      
      
      
      
      
      
      
        
       
       
       
       super
       
       
       
       .
       
       
       
       onCreate
       
       
       
       (
       
       
       
       db
       
       
       
       );

      
      
      
      
      
      
      
      
        
       
       
       
       executeMigrations
       
       
       
       (
       
       
       
       db
       
       
       
       , 
       
       
       
       ALL_MIGRATIONS
       
       
       
       .
       
       
       
       keySet
       
       
       
       ());

      
      
      
      
      
      
      
      
    
       
       
       
       }

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      
    
       
       
       
       @Override

      
      
      
      
      
      
      
      
    
       
       
       
       public 
       
       
       
       void 
       
       
       
       onUpgrade
       
       
       
       (
       
       
       
       SQLiteDatabase 
       
       
       
       sqLiteDatabase
       
       
       
       , 
       
       
       
       int 
       
       
       
       oldVersion
       
       
       
       , 
       
       
       
       int 
       
       
       
       newVersion
       
       
       
       ) 
       
       
       
       {

      
      
      
      
      
      
      
      
        
       
       
       
       LogUtil
       
       
       
       .
       
       
       
       w
       
       
       
       (
       
       
       
       SQLiteOpenHelper
       
       
       
       .
       
       
       
       class
       
       
       
       .
       
       
       
       getSimpleName
       
       
       
       (), 
       
       
       
       "Upgrade from" 
       
       
       
       + 
       
       
       
       oldVersion 
       
       
       
       + 
       
       
       
       "to" 
       
       
       
       + 
       
       
       
       newVersion
       
       
       
       );

      
      
      
      
      
      
      
      
        
       
       
       
       SortedMap
       
       
       
       <
       
       
       
       Integer
       
       
       
       , 
       
       
       
       Migration
       
       
       
       > 
       
       
       
       migrations 
       
       
       
       = 
       
       
       
       ALL_MIGRATIONS
       
       
       
       .
       
       
       
       subMap
       
       
       
       (
       
       
       
       oldVersion
       
       
       
       , 
       
       
       
       newVersion
       
       
       
       );

      
      
      
      
      
      
      
      
        
       
       
       
       executeMigrations
       
       
       
       (
       
       
       
       sqLiteDatabase
       
       
       
       , 
       
       
       
       migrations
       
       
       
       .
       
       
       
       keySet
       
       
       
       ());

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      
    
       
       
       
       }

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      
    
       
       
       
       private 
       
       
       
       void 
       
       
       
       executeMigrations
       
       
       
       (
       
       
       
       final 
       
       
       
       SQLiteDatabase 
       
       
       
       paramSQLiteDatabase
       
       
       
       , 
       
       
       
       final 
       
       
       
       Set
       
       
       
       <
       
       
       
       Integer
       
       
       
       >

      
      
      
      
      
      
      
      
            
       
       
       
       migrationVersions
       
       
       
       ) 
       
       
       
       {

      
      
      
      
      
      
      
      
        
       
       
       
       for 
       
       
       
       (
       
       
       
       final 
       
       
       
       Integer 
       
       
       
       version 
       
       
       
       : 
       
       
       
       migrationVersions
       
       
       
       ) 
       
       
       
       {

      
      
      
      
      
      
      
      
            
       
       
       
       ALL_MIGRATIONS
       
       
       
       .
       
       
       
       get
       
       
       
       (
       
       
       
       version
       
       
       
       ).
       
       
       
       migrate
       
       
       
       (
       
       
       
       paramSQLiteDatabase
       
       
       
       );

      
      
      
      
      
      
      
      
        
       
       
       
       }

      
      
      
      
      
      
      
      
    
       
       
       
       }

      
      
      
      
      
      
      
      

       
       
       
       }

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      

       
       
       
       /** 

      
      
      
      
      
      
      
      

       
       
       
        * Created by weijianxing on 9/22/15. 

      
      
      
      
      
      
      
      

       
       
       
        */

      
      
      
      
      
      
      
      

       
       
       
       public 
       
       
       
       interface 
       
       
       
       Migration 
       
       
       
       {

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      
    
       
       
       
       void 
       
       
       
       migrate
       
       
       
       (
       
       
       
       SQLiteDatabase 
       
       
       
       db
       
       
       
       );

      
      
      
      
      
      
      
      
    

      
      
      
      
      
      
      
      

       
       
       
       }

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      

       
       
       
       /** 

      
      
      
      
      
      
      
      

       
       
       
        * Created by weijianxing on 9/22/15. 

      
      
      
      
      
      
      
      

       
       
       
        */

      
      
      
      
      
      
      
      

       
       
       
       public 
       
       
       
       class 
       
       
       
       V1Migration 
       
       
       
       implements 
       
       
       
       Migration 
       
       
       
       {

      
      
      
      
      
      
      
      


      
      
      
      
      
      
      
      
    
       
       
       
       @Override

      
      
      
      
      
      
      
      
    
       
       
       
       public 
       
       
       
       void 
       
       
       
       migrate
       
       
       
       (
       
       
       
       SQLiteDatabase 
       
       
       
       db
       
       
       
       ) 
       
       
       
       {

      
      
      
      
      
      
      
      
        
       
       
       
       db
       
       
       
       .
       
       
       
       execSQL
       
       
       
       (
       
       
       
       "ALTER TABLE NOTE ADD COLUMN test"
       
       
       
       );

      
      
      
      
      
      
      
      
    
       
       
       
       }

      
      
      
      
      
      
      
      

       
       
       
       }