Authorization identifiers, user authentication, and user authorization

When working with both user authentication and user authorization, you need to understand how user names are treated by each system.

If an external authentication system is used, the conversion of the user's name to an authorization identifier does not happen until after authentication has occurred but before user authorization. Imagine, for example, a user named Fred.

Within the user authentication system, Fred is known as FRed. Your external user authorization service is case-sensitive, so Fred must always type his name that way.
```
Connection conn = DriverManager.getConnection(
    "jdbc:derby:myDB", "FRed", "flintstone");
```
Within the Derby user authorization system, Fred becomes a case-insensitive authorization identifier. Fred is known as FRED.
When specifying which users are authorized to access the accounting database, you must list Fred's authorization identifier, FRED (which you can type as FRED, FREd, or fred, since the system automatically converts it to all-uppercase).
```
derby.fullAccessUsers=sa,FRED,mary
```

Let's take a second example, where Fred has a slightly different name within the user authentication system.

Within the user authentication system, Fred is known as Fred!. You must now put double quotes around the name, because it is not a valid SQL92Identifier. (Derby knows to remove the double quotes when passing the name to the external authentication system.)
```
Connection conn = DriverManager.getConnection(
    "jdbc:derby:myDB", "\"Fred!\"", "flintstone");
```
Within the Derby user authorization system, Fred becomes a case-sensitive authorization identifier. Fred is known as Fred!.
When specifying which users are authorized to access the accounting database, you must list Fred's authorization identifier, "Fred!" (which you must always delimit with double quotation marks).
```
derby.fullAccessUsers=sa,"Fred!",manager
```

As shown in the first example, your external authentication system may be case-sensitive, whereas the authorization identifier within Derby may not be. If your authentication system allows two distinct users whose names differ by case, delimit all user names within the connection request to make all user names case-sensitive within the Derby system. In addition, you must also delimit user names that do not conform to SQL92Identifier rules with double quotes.