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  • SQLiteHelper

     1 /**
     2  * 实现对表的创建、更新、变更列名操作
     3  *
     4  *
     5  */
     6 public class SQLiteHelper extends SQLiteOpenHelper {
     7     public static final String DB_NAME = "historyDB";
     8     public static final String TB_NAME = "historyTB";
     9     
    10     public SQLiteHelper(Context context)
    11     {
    12         super(context, DB_NAME, null, 1);
    13     }
    14     
    15     /**
    16      * 创建新表
    17      */
    18     @Override
    19     public void onCreate(SQLiteDatabase db) {
    20         db.execSQL("CREATE TABLE IF NOT EXISTS " +
    21                 TB_NAME + "(" +
    22                 //HistoryBean.ID + " integer primary key," +
    23                 HistoryBean.URL + " varchar," + 
    24                 HistoryBean.TIME + " integer,"+
    25                 HistoryBean.NAME + " varchar"+
    26                 ")");
    27     }
    28     
    29     /**
    30      * 当检测与前一次创建数据库版本不一样时,先删除表再创建新表
    31      */
    32     @Override
    33     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    34         db.execSQL("DROP TABLE IF EXISTS " + TB_NAME);
    35         onCreate(db);
    36     }
    37     
    38     /**
    39      * 变更列名
    40      * @param db
    41      * @param oldColumn
    42      * @param newColumn
    43      * @param typeColumn
    44      */
    45     public void updateColumn(SQLiteDatabase db, String oldColumn, String newColumn, String typeColumn){
    46         try{
    47             db.execSQL("ALTER TABLE " +
    48                     TB_NAME + " CHANGE " +
    49                     oldColumn + " "+ newColumn +
    50                     " " + typeColumn
    51             );
    52         }catch(Exception e){
    53             e.printStackTrace();
    54         }
    55     }
    56 
    57 }
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  • 原文地址:https://www.cnblogs.com/xmb7/p/3190664.html
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