Sometimes it is necessary to rename fields in order to obtain the desired associations. The three main reasons for renaming fields are:
- Two fields are named differently although they denote the same thing:
- The field ID in the Customers table
- The field CustomerID in the Orders table
The two fields denote a specific customer identification code and should both be named the same, for example CustomerID.
- Two fields are named the same but actually denote different things:
- The field Date in the Invoices table
- The field Date in the Orders table
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There may be errors such as misspellings in the database or different conventions on upper- and lowercase letters.
The two fields should preferably be renamed, to for example InvoiceDate and OrderDate.
Since fields can be renamed in the script, there is no need to change the original data. There are two different ways to rename fields as shown in the examples.
Example 1: Using the alias statement
The LOAD or SELECT statement can be preceded by an alias statement.
Alias ID as CustomerID;
LOAD * from Customer.csv;
Example 2: Using the as specifier
The LOAD or SELECT statement can contain the as specifier.
LOAD ID as CustomerID, Name, Address, Zip, City, State from Customer.csv;