android -在SQLite中防止重复插入数据
android -在SQLite中防止重复插入数据
提问于 2018-01-25 21:12:18
我刚学会在android上使用sqlite。如何在插入数据时防止重复数据。那么，当有相同的数据条目时，它会覆盖数据吗？
这里我附加了代码片段：
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_FAVORIT_TABLE = "CREATE TABLE " + Constant.favoritDBtable + "("
+ Constant.id_postFav + " INTEGER PRIMARY KEY AUTOINCREMENT," + Constant.titleFav + " TEXT," + Constant.namaPerusahaanFav + " TEXT,"
+ Constant.lokasiFav + " TEXT," + Constant.kriteria_1Fav + " TEXT," + Constant.kriteria_2Fav
+ " TEXT," + Constant.kriteria_3Fav + " TEXT," + Constant.gajiFav + " TEXT," + Constant.img_logoFav
+ " TEXT," + Constant.tanggalFav + " TEXT);";
public String addFavorit(Favorit favorit){
SQLiteDatabase db = this.getWritableDatabase();
// long rows = 0;
ContentValues values = new ContentValues();
values.put(Constant.titleFav, favorit.getTitleFav());
values.put(Constant.namaPerusahaanFav, favorit.getNamaPerusahaanFav());
values.put(Constant.lokasiFav, favorit.getLokasiFav());
values.put(Constant.kriteria_1Fav, favorit.getKriteria_1Fav());
values.put(Constant.kriteria_2Fav, favorit.getKriteria_2Fav());
values.put(Constant.kriteria_3Fav, favorit.getKriteria_3Fav());
values.put(Constant.gajiFav, favorit.getGajiFav());
values.put(Constant.img_logoFav, favorit.getImg_logoFav());
values.put(Constant.tanggalFav, favorit.getTanggalFav());
db.insert(Constant.favoritDBtable, null, values,);
Log.d("Favorit saved: ", "Success 200 OK");
return null;
}MainActivity.java
@Override
public void onClick(View v) {
if (job.getTitle() != null && job.getLokasi() != null){
saveToFavoritDB();
}
}
private void saveToFavoritDB() {
Favorit favorit = new Favorit();
favorit.setTitleFav(job.getTitle());
favorit.setGajiFav(job.getGaji());
Log.d(TAG, "gaji " + job.getGaji());
db.addFavorit(favorit);
List<Favorit> favList = db.getAllFavorit();
for (Favorit each : favList) {
String log = "ID: " + each.getTitleFav() + ", Name: " + each.getLokasiFav() + ", Phone: " + each.getGajiFav();
Log.d(TAG, "saveToFavoritDB: " + String.valueOf(db.getCountFavorit()));
Log.d(TAG, "Hasil: " + log);
}
}希望你能帮助我
回答 3
Stack Overflow用户
回答已采纳
发布于 2018-01-25 22:35:34
在使用addFavorit方法之前，您可以添加一个方法来检查数据是否已经存在，以防止重复。
boolean check;
check = checkDuplicate(...,...,...,id_post); // check whether data exists
if(check == true) // if exists
{
Toast.makeText(MainActivity.this, " Data Already Exists", Toast.LENGTH_LONG).show();
}else{
db.addFavorit(favorit);
}
public static boolean checkDuplicate(String TableName,String dbfield, String fieldValue, int id_post) {
String Query = ".... WHERE "+ Constant.id_postFav +"="+ id_post; // your query
Cursor cursor = db.rawQuery(Query, null);
if(cursor.getCount() <= 0){
cursor.close();
return false;
}
cursor.close();
return true;
}Stack Overflow用户
发布于 2018-01-25 22:20:22
创建用于检查行是否在数据库中的函数
private static boolean CheckIsInDBorNot(String titleFav) {
String selectQuery = "SELECT * FROM " + Constant.favoritDBtable + " WHERE " + Constant.titleFav +"'"+titleFav "'";
final SQLiteDatabase db = open();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.getCount() <= 0) {
cursor.close();
return false;
}
cursor.close();
return true;
}然后检查
if (!CheckIsInDBorNot(commentOrderId, commentId)) {
db.insertOrThrow(Constant.favoritDBtable, null, cVal);
}它将检查并插入
Stack Overflow用户
发布于 2018-06-18 20:44:46
在DatabaseHelper类中创建方法IsItemExist()，并在activity类中调用此方法，如IsItemExist(name,mobile)
public boolean IsItemExist(String name,String mobile) {
try
{
SQLiteDatabase db=this.getReadableDatabase();
Cursor cursor=db.rawQuery("SELECT "+NAME+" FROM "+TABLE+" WHERE "+NAME+"=?",new String[]{name});
Cursor cursor1=db.rawQuery("SELECT "+MOBILE+" FROM "+TABLE+" WHERE "+MOBILE+"=?",new String[]{mobile});
if (cursor.moveToFirst() && cursor1.moveToFirst())
{
db.close();
Log.d("Record Already Exists", "Table is:"+TABLE+" ColumnName:"+NAME);
return true;//record Exists
}
Log.d("New Record ", "Table is:"+TABLE+" ColumnName:"+NAME+" Column Value:"+NAME);
db.close();
}
catch(Exception errorException)
{
Log.d("Exception occured", "Exception occured "+errorException);
// db.close();
}
return false;
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/48443705
复制相关文章
相似问题
腾讯云开发者
