What does it mean to qualify a field name?

Answer 1

A field is the name given to the column or attribute. A field name cannot be empty and also it cannot be an identifier. Example in a table stud there are fields like Fname, Lname, Rollno etc

A fully qualified field name in simple terms is the table name in which the field resides and the field name. As an example we have a table called Customers and a field FirstName Within a query you cold point to or declare the field name as simply FirstName. Now if you are joining a couple of tables and each has the field name FirstName you would need to fully qualify the field so that the database would know from which table you wanted the FirstName data. So in this example lets say we have the tables Customers and Employee. Within the Customers table we have a EmployeeID field that ties an employee (maybe the employee that entered the customer) to the customer. Now in a query you want to display the Customer's first name. In this case you would need to specify the table name WITH the field name in order to present a result. Example: Customers.FirstName or Employee.FirstName You could further qualify the field by including the database names as well. This is NOT common however if you are using multiple databases in a query then you would need to.

Answer 2

You need a mechanism for indication the REP_NUM column to which you are referring. One common approach o solving this problem is to write both the table name and the column name, separated by a period. Thus, the REP_NUM column in the CUSTOMER table is written as CUSTOMER.REP_NUM, whereas the REP_NUM column in the REP table is written as REP.REP_NUM. Technically, when you write columns in this format, you say that you qualify the name. It is always acceptable to qualify column names, even if there is no potential for confusion. If confusion might arise, however, it is essential to qualify column names.

Answer 3

A field is the name given to the column or attribute. A field name cannot be empty and also it cannot be an identifier. Example in a table stud there are fields like Fname, Lname, Rollno etc

Answer 4

A fully qualified field name in simple terms is the table name in which the field resides and the field name. As an example we have a table called Customers and a field FirstName Within a query you cold point to or declare the field name as simply FirstName. Now if you are joining a couple of tables and each has the field name FirstName you would need to fully qualify the field so that the database would know from which table you wanted the FirstName data. So in this example lets say we have the tables Customers and Employee. Within the Customers table we have a EmployeeID field that ties an employee (maybe the employee that entered the customer) to the customer. Now in a query you want to display the Customer's first name. In this case you would need to specify the table name WITH the field name in order to present a result. Example: Customers.FirstName or Employee.FirstName You could further qualify the field by including the database names as well. This is NOT common however if you are using multiple databases in a query then you would need to.