vb.net generate qr barcode Overview of the JDBC Process in Java

Encoding PDF-417 2d barcode in Java Overview of the JDBC Process

Overview of the JDBC Process
PDF 417 Maker In Java
Using Barcode encoder for Java Control to generate, create PDF417 image in Java applications.
Recognize PDF 417 In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
Although each J2ME application is different, J2ME applications use a similar process for interacting with a DBMS This process is divided into five routines: loading the JDBC driver, connecting to the DBMS, creating and executing a statement, processing data returned by the DBMS, and terminating the connection with the DBMS It is sometimes better to get a general understanding of how the process works before delving into the details of each routine of the process Therefore, the next few sections provide an overview of the process and each routine A more detailed discussion of each routine is provided later in this chapter
Creating Bar Code In Java
Using Barcode encoder for Java Control to generate, create barcode image in Java applications.
Decode Bar Code In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
Generating PDF 417 In Visual C#
Using Barcode encoder for VS .NET Control to generate, create PDF417 image in Visual Studio .NET applications.
Create PDF417 In .NET Framework
Using Barcode printer for ASP.NET Control to generate, create PDF417 image in ASP.NET applications.
JDBC Objects
Painting PDF 417 In VS .NET
Using Barcode encoder for Visual Studio .NET Control to generate, create PDF-417 2d barcode image in .NET framework applications.
Drawing PDF 417 In Visual Basic .NET
Using Barcode creator for VS .NET Control to generate, create PDF 417 image in .NET framework applications.
Load the JDBC Driver
Bar Code Printer In Java
Using Barcode printer for Java Control to generate, create bar code image in Java applications.
ECC200 Creation In Java
Using Barcode generation for Java Control to generate, create Data Matrix 2d barcode image in Java applications.
The JDBC driver must be loaded before the J2ME application can connect to the DBMS The ClassforName() method is used to load the JDBC driver Suppose a developer wants to work offline and write a J2ME application that interacts with Microsoft Access on the developer s PC The developer must write a routine that loads the JDBC/ODBC Bridge driver called sunjdbcodbcJdbcOdbcDriver The driver is loaded by calling the ClassforName() method and passing it the name of the driver, as shown in the following code segment:
Creating GS1 DataBar In Java
Using Barcode generator for Java Control to generate, create GS1 DataBar Stacked image in Java applications.
Print Code 39 Extended In Java
Using Barcode creation for Java Control to generate, create Code 39 Full ASCII image in Java applications.
ClassforName( "sunjdbcodbcJdbcOdbcDriver");
UPC - E0 Maker In Java
Using Barcode generator for Java Control to generate, create UCC - 12 image in Java applications.
2D Barcode Encoder In .NET
Using Barcode creation for ASP.NET Control to generate, create Matrix Barcode image in ASP.NET applications.
Connect to the DBMS
Bar Code Drawer In None
Using Barcode encoder for Excel Control to generate, create bar code image in Excel applications.
EAN-13 Supplement 5 Maker In None
Using Barcode creator for Microsoft Word Control to generate, create EAN 13 image in Office Word applications.
Once the driver is loaded, the J2ME application must connect to the DBMS using the DriverManagergetConnection() method The javasqlDriverManager class is the highest class in the javasql hierarchy and is responsible for managing driver information The DriverManagergetConnection() method is passed the URL of the database, along with the user ID and password if required by the DBMS The URL is a String object that contains the driver name and the name of the database that is being accessed by the J2ME application The DriverManagergetConnection() returns a Connection interface that is used throughout the process to reference the database The javasqlConnection interface is another member of the javasql package that manages communications between the driver and the J2ME application It is the javasqlConnection interface that sends statements to the DBMS for processing Listing 10-1 illustrates the use of the DriverManagergetConnection() method to load the JDBC/ODBC Bridge and connect to the CustomerInformation database
Code-128 Printer In Objective-C
Using Barcode encoder for iPhone Control to generate, create Code 128B image in iPhone applications.
Code 128C Generator In None
Using Barcode printer for Software Control to generate, create Code 128A image in Software applications.
Listing 10-1 Open a connection with a database
Generate GS1 - 13 In C#
Using Barcode drawer for Visual Studio .NET Control to generate, create EAN-13 Supplement 5 image in VS .NET applications.
Reading Barcode In Java
Using Barcode Control SDK for BIRT reports Control to generate, create, read, scan barcode image in BIRT reports applications.
String url = "jdbc:odbc:CustomerInformation"; String userID = "jim"; String password = "keogh"; Statement DataRequest; private Connection Db; try { ClassforName( "sunjdbcodbcJdbcOdbcDriver"); Db = DriverManagergetConnection(url,userID,password); }
Create and Execute an SQL Statement
The next step after the JDBC driver is loaded and a connection is successfully made with a particular database managed by the DBMS is to send an SQL query to the DBMS for
J2ME: The Complete Reference
processing An SQL query consists of a series of SQL commands that direct the DBMS to do something, such as return rows of data to the J2ME application You ll learn how to write queries in the next chapter The ConnectcreateStatement() is used to create a Statement object The Statement object is then used to execute a query and return a ResultSet object that contains the response from the DBMS, which is usually one or more rows of information requested by the J2ME application Typically, the query is assigned to a String object, which is passed to the Statement object s executeQuery() method, as illustrated in the next code segment Once the ResultSet is received from the DBMS, the close() method is called to terminate the statement Listing 10-2 retrieves all the rows and columns from the Customers table
Listing 10-2 Retrieve all the rows from the Customers table
Statement DataRequest; ResultSet Results; try { String query = "SELECT * FROM Customers"; DataRequest = DatabasecreateStatement(); DataRequest = DbcreateStatement(); Results = DataRequestexecuteQuery (query); DataRequestclose(); }
Process Data Returned by the DBMS
The javasqlResultSet object is assigned the results received from the DBMS after the query is processed The javasqlResultSet object consists of methods used to interact with data that is returned by the DBMS to the J2ME application Later in this chapter you ll learn the details of using the javasqlResultSet object However, the following code is an abbreviated example that gives you a preview of a commonly used routine for extracting data returned by the DBMS Error-catching code is purposely removed from this example in order to minimize code clutter You ll find the completed version of this routine later in this chapter and throughout 11 Assume for Listing 10-3 that a J2ME application requested a customer s first name and last name from a table The result returned by the DBMS is already assigned to the ResultSet object called Results The first time that the next() method of the ResultSet is called, the ResultSet pointer is positioned at the first row in the ResultSet and returns a boolean value If false, this indicates that no rows are present in the ResultSet The if statement in Listing 10-3 traps this condition and displays the End of data message on the screen A true value returned by the next() method means at least one row of data is present in the ResultSet, which causes the code to enter the do while loop The getString() method of the ResultSet object is used to copy the value of a specified column in the current row of the ResultSet to a String object The getString() method is passed the name of the column in the ResultSet whose content needs to be copied, and the getString() method returns the value from the specified column
Copyright © OnBarcode.com . All rights reserved.