Constraints

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

Hi,

I would like to ad Constraints to a database column, which only can have
unique values. The column can be empty only if the table is empty (no
records).

Im using the syntaxt:
pk = new DataColumn[1];
pk[0] = ds.Tables["table"].Columns["ID"];
ds.Tables["table"].Constraints.Add(new UniqueConstraint("ConstrName", pk[0]));
ds.Tables["table"].PrimaryKey = pk;

The problem is when the datatable is empty. I get an error message "the
column doesn't contain the unique value".

Is it possible to avoid this with an empty table?

Thanks,
Lubomir
 
Lubomir said:
Hi,

I would like to ad Constraints to a database column, which only can have
unique values. The column can be empty only if the table is empty (no
records).

Im using the syntaxt:
pk = new DataColumn[1];
pk[0] = ds.Tables["table"].Columns["ID"];
ds.Tables["table"].Constraints.Add(new UniqueConstraint("ConstrName", pk[0]));
ds.Tables["table"].PrimaryKey = pk;

The problem is when the datatable is empty. I get an error message "the
column doesn't contain the unique value".

Is it possible to avoid this with an empty table?

Thanks,
Lubomir
Click to expand...

Well, I've found and error already (a mistake in the table name when next
table was added to a dataset).
 
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