The Qsqlrelationaltablemodel SELECT statement will change the name of the column

Don't explain what Qsqlrelationaltablemodel is. Look at the following code:

        3.1 Create model        model = new Qsqlrelationaltablemodel ();        Model->settable ("tyzb_xmmx");        Model->setfilter (filter);        Model->setsort (Tyzb_xmmx::xh,qt::ascendingorder);        3.2 The Foreign key column displays the problem        model->setrelation (tyzb_xmmx::d wdm_id,qsqlrelation ("DM_DWDM", "DWDM", "DWMC"));        Model->setrelation (Tyzb_xmmx::xmlb_id,qsqlrelation ("dm_xmlb", "XH", "LBMC"));        Model->setrelation (Tyzb_xmmx::zydm_id,qsqlrelation ("DM_ZYDM", "XH", "ZYMC"));        Model->setrelation (Tyzb_xmmx::zjxx_id,qsqlrelation ("Tyzb_zjxx", "XH", "ZJXM"));        Model->setjoinmode (Qsqlrelationaltablemodel::leftjoin); Rows that have a foreign key column blank are also displayed
        

Some of the rest of the code is omitted, such as setting the column header display, adjusting the Qtableview, and then calling the following code:

    //4 Execute QueryQsqlrecord r = model->record ();    Qstringlist FieldNames;  for(inti =0; i< Model->columncount (); i++) {fieldnames.append (R.fieldname (i)); } qdebug ()<< Fieldnames.join (','); Model-Select(); R= model->record ();    Fieldnames.clear ();  for(inti =0; i< Model->columncount (); i++) {fieldnames.append (R.fieldname (i)); }qdebug ()<< Fieldnames.join (',');

View the output of the next qdebug:

  xh,createdate,bz,isdelete,lastoperate , Bnd,jzsj,xmmc,nd,ndyq,qssj,xmbh,xmdm,xmsqs,yjnryq,yap,zszjyj,zgs,, xmlb_id , zjxx_id , Gjz,zydm_id , ZYPX,HCMC   " "  xh,createdate,bz,isdelete,lastoperate,bnd,jzsj,xmmc,nd,ndyq,qssj,xmbh,xmdm,xmsqs,yjnryq,yap,zszjyj,zgs,DWMC , LBMC , zjxm , Gjz,ZYMC , ZYPX,HCMC   " 

What is found, the column name of the column with the foreign key has been updated by the SELECT statement to the foreign key display column, if you also call the following statement after the SELECT statement to get the column ordinal, it will be an error, in particular, return-1:

  Model->fieldindex ("zydm_id");   Returns-1

As a comparison, it continues to be called on the model that executed the SELECT call:

    R = Model->record (0);     << R.field (Model->fieldindex ("zymc"));     << R.field (Model->fieldindex ("zymc")). Value ();

Returns the following information:

Qsqlfield ("zymc"7650253false   "collection and Recovery Center ")

That is, the display value of the foreign key is returned, not the foreign key value itself.

So, can you get the original zydm_id value directly in the model? There is no good way to find it, only re-create a qsqlquery statement, based on the primary key XH get:

    Qsqlquery GETZYDM (QString ("select zydm_id from tyzb_xmmx where xh=%1"). Arg (R.value ( TYZB_XMMX::XH). toString ()));     if (Getzydm.first ())         << Getzydm.value (0);

The key value of the foreign key is returned: qvariant (Qlonglong, 7),
It's a very discordant and elegant way! Temporarily so, there is no better please passers-by pointing twos!

The Qsqlrelationaltablemodel SELECT statement will change the name of the column