Question

I have three database tables defined below, column names mentioned in parenthesis:

Product (ProductID, Price, Last_Updated)

User (UserID, Name, Address, LocationID, Last_Updated)

Location (LocationID, Loc_Name, Last_Updated)

I want to use Java (JDK 1.5) to add all the column names of all the tables in one collection like a HashMap.

My problem is when a duplicate key is entered, the previous value is over ridden.

I am adding them like:

Map<String, String> map = new HashMap<String, String>();

map.add("ProductID", "Save the Product ID");
// ...
map.add("Last_Updated", "Save Last_Updated of Product table");
// ...
map.add("LocationID", "Save the LocationID");
// ...
map.add("Last_Updated", "Save Last_Updated of User table.");

Now the key Last_Updated is overridden with new value Save Last_Updated of User table.

But I want both the values.

Is there any way to implement this without using multiple HashMap structures?

Answer 1

Add the table names as a prefix to your column names. Then you can separate “Product.Last_Updated”, “User.Last_Updated” and “Location.Last_Updated”.
Obviously you have to use a separator char that is not used in the names of your tables or columns; a ‘.’ should do.