Dynamic field renaming with mapping table from list of loaded fields

[Anonymous]

Hi,

I'm trying to dynamically rename loaded fields --- specifically I'm trying to rename fields that start with PK_ (primary key) into starting with FK_ (which means foreign key, but QV requires the same name, so FK_ it is.)

So, I loop through the fields and build a mapping table, which looks fine except that it doesn't work. Can anyone tell me why? 🙂

// Data
tab1:
LOAD * Inline [
FK_xxx,Country
1,USA
2,Canada
3,UK];

tab2:
LOAD * Inline [
PK_xxx,Continent
1,North America
2,North America
3,Europe
];

// For all tables, get field names, put them in table called f_names, field called FName
for ii=1 to NoOfTables()-1  // -1 here because otherwise f_names table itself is included
  for jj=1 to NoOfFields(TableName($(ii)) )
       f_names:
       LOAD FieldName($(jj),TableName($(ii))) as FName
       Autogenerate 1;
   next
next


// Make mapping table
map_1:
mapping LOAD trim(FName) as xxx, trim('FK_' & mid(FName,4,len(FName)-3)) as Map_into
Resident f_names
where wildmatch(FName,'PK_*','GK_*') <> 0;

// Copy of mapping table for debugging purposes
LOAD trim(FName) as xxx, trim('FK_' & mid(FName,4,len(FName)-3)) as Map_into
Resident f_names
where wildmatch(FName,'PK_*','GK_*') <> 0;

drop table f_names;

// Everything seems fine until here, this command seemingly gets ignored -- or is the mapping table wrong?
RENAME Fields using map_1;

[Gysbert_Wassenaar · Accepted solution]

The problem is you already have a field FK_xxx, so you can't rename another field to FK_xxx. As the help file puts it:

Two differently named fields cannot be renamed to having the same name. The script will run without errors, but the second field will not be renamed.

[Anonymous]

Really?!  Hm, strange. But thank you very much!