Android 限制SQLite数据库条目
我开发了一个Android应用程序,它是一个试用版,用户只有有限的设备。。所以我想将用户输入限制为1。。。只有一个用户名可以注册。。结果显示必须限制为4,我必须为此做些什么。。我在下面给出代码Android 限制SQLite数据库条目,android,database,sqlite,Android,Database,Sqlite,我开发了一个Android应用程序,它是一个试用版,用户只有有限的设备。。所以我想将用户输入限制为1。。。只有一个用户名可以注册。。结果显示必须限制为4,我必须为此做些什么。。我在下面给出代码 package com.example.loginpage; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatab
package com.example.loginpage;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
public class DataBaseHelper extends SQLiteOpenHelper
{
public DataBaseHelper(Context context, String name,CursorFactory factory, int version)
{
super(context, name, factory, version);
}
// Called when no database exists in disk and the helper class needs
// to create a new one.
@Override
public void onCreate(SQLiteDatabase _db)
{
_db.execSQL(LoginDataBaseAdapter.DATABASE_CREATE);
}
// Called when there is a database version mismatch meaning that the version
// of the database on disk needs to be upgraded to the current version.
@Override
public void onUpgrade(SQLiteDatabase _db, int _oldVersion, int _newVersion)
{
// Log the version upgrade.
Log.w("TaskDBAdapter", "Upgrading from version " +_oldVersion + " to " +_newVersion + ", which will destroy all old data");
// Upgrade the existing database to conform to the new version. Multiple
// previous versions can be handled by comparing _oldVersion and _newVersion
// values.
// The simplest case is to drop the old table and create a new one.
_db.execSQL("DROP TABLE IF EXISTS " + "TEMPLATE");
// Create a new one.
onCreate(_db);
}
}
使用Select count COLUMN Name from tbalename和代码ifcount>=1{//Message to user}中的put条件从表中获取计数