2.2 Databases and Connections

In order for a DBTools.h++ application to open and use the connections required for interacting with a database, you must create an RWDBDatabase instance by calling:

RWDBManager::database(accessLib, serverName, userName,
                      passWord, databaseName);

These arguments, which are all of type RWCString, are used to build a connect string that is passed to the ODBC API function SQLDriverConnect(). This string takes the form:

DSN=serverName; PWD=passWord; DB=databaseName; UID=userName

The arguments you must provide to RWDBManager::database() are:

accessLib: If your DBTools.h++ access library is compiled as a DLL or shared library, provide the name of the DLL or shared library. See the Build Guide for information about naming conventions. If you are using a static library, supply the string "MS_SQL". This is a required parameter.

serverName: Supply the name of the SQL Server ODBC data source to which you are connecting, as found in your ODBC control panel (Windows), or your .odbc.ini file (Unix); for example, "mssql_driver". Alternatively, supply a full connect string of the form required by SQLDriverConnect(), and it will be passed to SQLDriverConnect() without modification; for example, "DSN=someDataSource;UID=user;PWD=password". This is a required argument.

userName: Supply the login of a valid user. Depending on the ODBC SQL Server data source settings, this may or may not be optional.

passWord: Supply the password for the user specified by userName. Depending on the Microsoft SQL Server ODBC data source settings, this may or may not be optional.
databaseName: You can optionally supply the name of a SQL server database to use. If this parameter is not supplied, the default database of the specified user is used.

Here are three examples of opening a database on a specific SQL server, INHOUSE.

The first example opens a specific database, ACCOUNTING. Notice that the accessLib is defined as MS_SQL, indicating that the application must be linked with the static version of the access library:

RWDBManager::database("MS_SQL", "INHOUSE", 
                      "cratchitt","scrooge","ACCOUNTING");

The second example shows opening the same database from a Windows NT or Windows 95 application. In this case, the accessLib is defined as msq4d.dll, indicating that the application will dynamically load the access library at runtime:

RWDBManager::database("msq4d.dll", "INHOUSE",
                      "cratchitt","scrooge","ACCOUNTING");

The final example demonstrates how to open a user's default database, which is the database assigned to the user by the database administrator:

RWDBManager::database("msq4d.dll", "INHOUSE",
                      "cratchitt", "scrooge", "");