Programming Tutorials

Using the DriverManager Class vs Using a DataSource Object for a connection

By: Reema Sen  

Using the DriverManager Class

The DriverManager class works with the Driver interface to manage the set of drivers available to a JDBC client. When the client requests a connection and provides a URL, the DriverManager is responsible for finding a driver that recognizes the URL and for using it to connect to the corresponding data source. Connection URLs have the following form:

jdbc:derby:<dbName>[propertyList]

The dbName portion of the URL identifies a specific database. A database can be in one of many locations: in the current working directory, on the classpath, in a JAR file, in a specific Java DB database home directory, or in an absolute location on your file system.

If you are using a vendor-specific driver, such as Oracle, the documentation will tell you what subprotocol to use, that is, what to put after jdbc: in the JDBC URL. For example, if the driver developer has registered the name OracleDriver as the subprotocol, the first and second parts of the JDBC URL will be jdbc.driver.OracleDriver . The driver documentation will also give you guidelines for the rest of the JDBC URL. This last part of the JDBC URL supplies information for identifying the data source.

The getConnection method establishes a connection:

Connection conn = DriverManager.getConnection("jdbc:derby:COFFEES");

In place of " myLogin " you insert the name you use to log in to the DBMS; in place of " myPassword " you insert your password for the DBMS. So, if you log in to your DBMS with a login name of " Fernanda " and a password of " J8, " just these two lines of code will establish a connection:

String url = "jdbc:derby:Fred";
Connection con = DriverManager.getConnection(url, "Fernanda", "J8");

If one of the drivers you loaded recognizes the JDBC URL supplied to the method DriverManager.getConnection, that driver establishes a connection to the DBMS specified in the JDBC URL. The DriverManager class, true to its name, manages all of the details of establishing the connection for you behind the scenes. Unless you are writing a driver, you probably won't use any of the methods in the interface Driver, and the only DriverManager method you really need to know is DriverManager.getConnection

The connection returned by the method DriverManager.getConnection is an open connection you can use to create JDBC statements that pass your SQL statements to the DBMS. In the previous example, con is an open connection, and you use it in the examples that follow.

Using a DataSource Object for a connection

Using a DataSource object increases application portability by making it possible for an application to use a logical name for a data source instead of having to supply information specific to a particular driver. The following example shows how to use a DataSource to establish a connection:

You can configure a DataSource using a tool or manually. For example, Here is an example of a DataSource lookup:

 InitialContext ic = new InitialContext()
 
 DataSource ds = ic.lookup("java:comp/env/jdbc/myDB");
 Connection con = ds.getConnection();
 DataSource ds = (DataSource) org.apache.derby.jdbc.ClientDataSource()
 ds.setPort(1527);
 ds.setHost("localhost");
 ds.setUser("APP")
 ds.setPassword("APP");
 
Connection con = ds.getConnection(); 

DataSource implementations must provide getter and setter methods for each property they support. These properties typically are initialized when the DataSource object is deployed.

VendorDataSource vds = new VendorDataSource();
vds.setServerName("my_database_server");
String name = vds.getServerName();

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