Testing for the existence of a field in a table

[gaby_h]

Pretty sure it's in the Field or Table Functions&Methods in the help file but couldn't find it after +2hrs of search and trial.
I am looking for a function that tests for the existence of a field in a table (the exact equivalent of Exist() but for field).
For expl I want to know if a field named "PartNumber" exists in Products table (table not open).
Thanks

[MikeC]

Re: Testing for the existence of a field in a table

Gaby,
Use the Index of the online help...type in Field.....choose functions (or use this link!)
http://support.alphasoftware.com/alp...nd_Methods.htm
Go to the is_valid() function....I think that is what you want.


EDIT--if not the use the .name_get() or A5_GET_FIELDNAMES() or <TBL>.FIELD_NAME_GET() to generate a list and then with the character list processing functions (such as is_one_of() or wordat()) you could determine if a specific name exists.

[gaby_h]

Re: Testing for the existence of a field in a table

Hi Mike:
I guessed I could use A5_GET_FIELDNAMES() or <TBL>.FIELD_NAME_GET() to generate a list and then test for the existence of a value in a list. But before using this approach, I wanted to make sure there was no simpler solution. Exist() is straightforward, I thought there was an equivalent function for Field.

[Stan Mathews]

Re: Testing for the existence of a field in a table

I guessed I could use A5_GET_FIELDNAMES() or <TBL>.FIELD_NAME_GET() to generate a list and then test for the existence of a value in a list.

Why "and then"? Why not all at once?



In AlphaSports

is_one_of("lastname",A5_GET_FIELDNAMES("customer"))
=.T.

[gaby_h]

Re: Testing for the existence of a field in a table

Thanks Stan, you saved me an unnecessary step.

[G Gabriel]

Re: Testing for the existence of a field in a table

Another approach:

table_flds=<<%str%
#fld_1
#fld_2
#fld_3%str%
?contains(table_flds,"fld_2")
= .T.
'Or
?"fld_2"$table_flds
= .T.

Another approach

t=table.open("tablename")
x=t.field_name_get()
?"fldname"$t.field_name_get()
= .T.
t.close()

Another approach

FUNCTION Field_exist AS L (tablename AS C, fieldname AS C )
	t=table.open(tablename)
	Field_exist=if(fieldname$t.field_name_get(),.t.,.f.)
        t.close()
END FUNCTION

In fact, in the above UDF, after adding the table name and if you righ-click on fieldname it should show available fields, I think.

[Al Buchholz]

Re: Testing for the existence of a field in a table

table_flds=<<%str%
fld_1
fld_2a
fld_2b
fld_3
%str%

?contains(table_flds,"fld_2")
= .F.

'Or
?"fld_2"$table_flds
= .T.

'Or
?"fld"$table_flds
= .T.

'Or
?is_one_of("fld_2",table_flds)
= .F.

'Or
?is_one_of("fld_2b",table_flds)
= .T.