我有一个数据库，我将在解析 JSON 响应后用项目填充该数据库。如何检查值是否已存在于数据库中并防止再次插入？

例如。数据库名称:Exicom.sqlite

表名:TimeReport

数据库中的字段:userID、clientName

我在 android 中使用 SQLite。

感谢您的参与

这是我的 HELPER 类。我已经跳过打开和关闭数据库，因为它太长了。接下来是我将在何处调用将值插入数据库的方法。

public static final String indexNo = "index_no";
public static final String user_id = "userId";
public static final String company_id = "companyId";
public static final String user_name = "username";
public static final String client_Id = "clientId";
public static final String project_Id = "projectId";
public static final String report_Id = "reportId";
public static final String niv_1  = "niv1";
public static final String niv_2 = "niv2";
public static final String work_type_id = "workTypeId";
public static final String time_type_id = "timeTypeId";
public static final String date_id = "dateId";
public static final String month_id = "monthId";
public static final String year_id = "yearId";
public static final String hourS = "hours";
public static final String private_comment = "privateComment";
public static final String Ncomment = "comment";
public static final String mod_flag = "modFlag";
public static final String new_flag = "newFlag";
public static final String open_flag = "openFlag";
public static final String delete_flag = "deleteFlag";

private static final String DATABASE_NAME = "CopernicusDB.sqlite";
private static final String DATABASE_TABLE = "TimeReportTable";
private static final int    DATABASE_VERSION = 1;

private final Context context;
private static DatabaseHelper DBHelper;
private static SQLiteDatabase db;
private static String TAG = "##---SecondActivityUserHelper---##";
public SecondActivityUserHelper(Context ctx)
{
this.context = ctx;
DBHelper = new DatabaseHelper(context);
}

private static class DatabaseHelper extends SQLiteOpenHelper{

    public DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        Log.v(TAG,"The DatabaseHelper method ");
    }

    public long insertIntoDatabase(String companyId,String username, String dateId,
            String clientId,String projectId,String niv1,String niv2,String workTypeId,String timeTypeId,
            String hours,String comment,String privateComment,String openFlag,String reportId) 
            {
            ContentValues initialValues = new ContentValues();
            initialValues.put(company_id, companyId);
            initialValues.put(user_name, username);
            initialValues.put(date_id,dateId);
            initialValues.put(client_Id,clientId);
            initialValues.put(project_Id,projectId);
            initialValues.put(niv_1,niv1);
            initialValues.put(niv_2,niv2);
            initialValues.put(work_type_id,workTypeId);
            initialValues.put(time_type_id,timeTypeId);
            initialValues.put(hourS, hours);
            initialValues.put(Ncomment, comment);
            initialValues.put(private_comment,privateComment);
            initialValues.put(open_flag, openFlag);
            initialValues.put(report_Id,reportId);
            Log.v(TAG, "Inserted into database sucessfully");
            return db.insert(DATABASE_TABLE, null, initialValues);
            }

useradapter.openDatabase();
long id = dB.insertIntoDatabase(  newcompanyid,newusername,newdate,
newClientId,newprojectId,newniv1,newniv2,newworktypeid,newtimetypeid,
newhours,newcomment,newprivatecomment,newopen,newreportid);
                             useradapter.closeDatabase();

最佳答案

创建一个对象来保存您的数据，例如。 客户端数据
创建一个从数据库中获取所有数据的方法

public List<ClientData> selectAll() {
   List<ClientData> list = new ArrayList<ClientData>();
   Cursor cursor = this.myDataBase.query(TABLE_NAME, new String[] { "userID, clientName" },
   null, null, null, null, null);
   if (cursor.moveToFirst()) {
        do {
           list.add(new ClientData(cursor.getString(0), cursor.getString(1)));
         } while (cursor.moveToNext());
   }
   if (cursor != null && !cursor.isClosed()) {
         cursor.close();
   }
   return list;
}

在执行插入语句之前，获取所有数据，然后检查数据是否存在:

if (!list.contains(clientData)) {
    executeInsert();
}

我不确定 SQLite 是否支持存储过程，但如果支持，您也可以为此编写一个存储过程。

关于android - 如何检查一个值是否已经存在于Android中的数据库中，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/7820905/