Question

我正在开发一个使用sqlite数据库的android应用程序。

主要问题： * 我一直面临这个错误没有这样的专栏，但我只是找不到导致这个问题的原因。任何意见将不胜感激。 *
次要问题： 我希望应用程序检查用户的信息是否在数据库内。如果它不存在，我希望系统能够处理某些事情。怎么做检查部分？我试过下面的东西。但由于没有这样的专栏问题，我不确定它是否有效。
```
                String values[] = helper.get_synccontentByEmailID(SettingConstant.EMAIL);
            if(!(values[0] == null)){


            }
```

- 数据库类 -

    public void onCreate(SQLiteDatabase db) {

    db.execSQL("CREATE TABLE synccontent (" + 
            "tableid INTEGER PRIMARY KEY AUTOINCREMENT, " +
            "emailid_sync TEXT " +
            "contentid TEXT," +
            "contentpath TEXT," +
            "filesize TEXT," +
            "createdtime TEXT,"+
            "createdate TIMESTAMP default current_timestamp);");
}
public String[] get_synccontentByEmailID(String emailid_sync){
    SQLiteDatabase myDB = null;
    String[] returnMsg = null;
    myDB = this.getReadableDatabase();

    Cursor c = myDB.rawQuery("SELECT tableid, emailid_sync, contentid, contentpath, filesize, createdtime" +
            " from synccontent where emailid_sync='"+emailid_sync+"' ", null);
    int emailid_syncColumn = c.getColumnIndex("emailid_sync");              
    int contentidColumn = c.getColumnIndex("contentid");
    int contentpathColumn = c.getColumnIndex("contentpath");
    int filesizeColumn = c.getColumnIndex("filesize");
    int createdtimeColumn = c.getColumnIndex("createdtime");

    if (c.moveToFirst()) {
        do {
            returnMsg = new String[5]; 
            String contentid = c.getString(contentidColumn);
            String contentpath = c.getString(contentpathColumn);
            String filesize = c.getString(filesizeColumn);
            String createdtime = c.getString(createdtimeColumn);

            returnMsg[0] = emailid_sync;
            returnMsg[1] = contentid;
            returnMsg[2] = contentpath;
            returnMsg[3] = filesize;
            returnMsg[4] = createdtime;

        } while (c.moveToNext());
    }

- 主要活动 -

    syncButton = (Button) findViewById(R.id.sync_btn);
    syncButton.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View v) {

                    String values[] = helper.get_synccontentByEmailID(SettingConstant.EMAIL);
                if(!(values[0] == null)){


                }





E/AndroidRuntime(4543): android.database.sqlite.SQLiteException: no such column: contentid: , while compiling: SELECT tableid, emailid_sync, contentid, contentpath, filesize, createdtime from wbm_synccontent where emailid_sync='testing@yahoo.com'

Answer 1

Primary Issue

也许您首先创建了没有contentId的表。然后添加了新列contentId.But表没有重新创建。要重新创建表，db再次卸载应用程序，然后重新安装。

Secondary Issue

你可以这样做

Cursor c = myDB.rawQuery("SELECT * from synccontent where emailid_sync='"+emailid_sync+"' ", null);
if(c.getCount()==0){       //not in db
}

Answer 2

emailid_sync TEXT之后缺少逗号。

db.execSQL("CREATE TABLE synccontent (" + 
            "tableid INTEGER PRIMARY KEY AUTOINCREMENT, " +
            "emailid_sync TEXT, " +
            "contentid TEXT," +
            "contentpath TEXT," +
            "filesize TEXT," +
            "createdtime TEXT,"+
            "createdate TIMESTAMP default current_timestamp);");

这应该解决主要问题，在另一个答案中给出了二级解决方案。我认为没关系。

错误：没有这样的列

2 个答案: