I know–that’s already covered by what you told him–just curious. Importing class you will have extra dependency From The Java Tutorial: The program above contains the statement: However, you must manually load any drivers prior to JDBC 4. Driver” ; as I tried to import com. There are two possibilities. Second way of loading a class is to simply creating an instance of it using new.
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How does DriverManager class know how to get the connection without using class name of the actual driver. Second way of loading a class is to simply creating an instance of it using new. You need to write a simple program that does nothing but connect to the database.
Much of the database logic is the same, but you can see that a TextListener is added to listen to the TextFieldso that sun.jdbc.odbc.dbcodbcdriver you type a new character it first tries to do a name completion by looking up the last name in rhe database and using the first hhe that shows up. SQL has another way to insert names into a query called stored procedureswhich is used for speed.
I know–that’s already covered by what you told him–just curious. Sign up using Email and Password.
The discrepancies between database products are just something that JDBC tries to help compensate for. It will not ‘start the class’.
I apologize for that. When we create an instace of a class using new operator, it does two things Load the class in to memory, if it is not loaded – which means creating in-memory representation of the class from the. This is the result of doing what you said: Is the problem that Class.
To test whether your driver load statement is working correctly, comment out the code after the statement and up ckass.forname the catch clause; if the program throws no exceptions it means that the driver is loading properly. Then when DriverManager needs to find a driver for a particular connection string, it calls acceptsURL on each registered driver in turn until one says, “Yes, I can be the driver for that connection.
The basic idea behind using Class. If that’s so, i think that it is very limiting No, that’s not the case.
So when we call Class. However, you must manually load any drivers prior to JDBC 4. There are some overloads to Class.
The program above contains the statement: MyClass or java -classpath. It will load it and perform its static initialization. As mentioned earlier, databases have seemed from their inception to be in thhe constant state of turmoil, primarily because the demand for database applications, and thus database tools, is so great.
In this example, there is no password protection on the database so the user name and password are empty strings. This makes it more obvious where the code will fail throw an exception if that class is not present in the classpath when that code runs.
I used Microsoft Query that came with Microsoft Office, but you might prefer something else. If you simply import the class and then reference it in your code, it becomes slightly less obvious where the code will throw an exception if the class is not present. The driver objects register themselves with the driver manager at the time of loading, and you can force the sun.jdbc.odbc.jdbcodbcdeiver using Class.
This drag and drop mechanism internally requires certain classes to be loaded at run time.