The double colon (::) is a short-hand syntax
for referencing constant named members of database object containers,
for example dynamic ProDataSets, queries, temp-tables, and buffers.
The
following rules will help you to decide whether to use dot, colon,
or double colon syntax:
- Use a dot between two names when
the left-hand side name is the actual name of a database or table,
known at compile time, and is not a handle or reference of any kind.
For example, Customer.CustNum or Sports2000.Customer or Sports2000.Customer.CustNum.
- Use a colon between two character strings when the left-hand
side is a handle or reference, and is not the actual name of a database
or table, and the right-hand side is an attribute or method for
the left-hand-side handle or reference. For example, hBuff:NUM-FIELDS, or hDset:NUM-BUFFERS or hBuff:FIND-FIRST.
- Use a double colon between two character strings when the left-hand side
name is a handle to a container object of some kind (buffer, table
or ProDataSet) and the right-hand side is not an attribute or method,
but instead is a named member of the left-hand side. For example, hBuff::CustNum or hDset::Customer or hDSet::Customer::CustNum.
For
example, if hBuff is a HANDLE to the Customer table,
then hBuff:NAME returns the string "Customer",
but hBuff::NAME returns the value of the NAME field
for the current record in the hBuff Buffer, e.g. "Lift
Line Skiing".
