android sqlite 升级数据库

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1.创建表

String sql = "CREATE TABLE IF NOT EXISTS " + “表名”
        + " (_id INTEGER PRIMARY KEY AUTOINCREMENT,"
        + "列名 TEXT," + "列名 INT)";
db.execSQL(sql);

2.表新增列

String sql = "ALTER TABLE " + “表名” + " ADD " + “列名” + " TEXT";

db.execSQL(sql);

3.表的某列全部替换数据

String sql = "UPDATE " + “表名” + " SET " + “列名” + " = '需要替换的内容'";
db.execSQL(sql);

4.删除某个表

String sql_s = "DELETE FROM " + “表名”;
db.execSQL(sql_s);

5.假设你的项目是IM即时聊天，DB中的消息表是以(message_+聊天对象的id)组成的，比如message_123和message_456,现在我想对所有消息表都加个字段，应该这么处理：

Cursor cursor = null;
// 所有消息表添加messageType字段
cursor = db.rawQuery("SELECT name FROM sqlite_master WHERE type='table' AND name LIKE ?",
new String[]{"message_%"});
while (cursor.moveToNext()) {
        String sql = "ALTER TABLE " + cursor.getString(0) + " ADD " + "messageType" + " TEXT";
        db.execSQL(sql);
}

6.A表数据迁移到B表

insert into “B表表名”(_id,“B表列名1”,“B表列名2”) select null,“A表列名1”,“A表列名2” from “A表表名”

传null是因为_id是自增主键。

7.其它等我用到再补充。单纯做个笔记。哈哈。