Updated July 6, 2023
Introduction to JDBC connection
Java Database Connectivity is the API designed for Java that manages to associate the database with the help of commands and queries that can handle the result set got from the database. The Java persistence layer has its first component as JDBC and defines the client which accesses the database. It offers several methods to query and feed the data into the relational database. The JDBC API requires each driver to connect with an individual database. The steps to connect with the database are discussed in this article.
What is the JDBC connection?
The JDBC is a software application that allows the application in Java to communicate with the database. They are similar to ODBC drivers, OLE DB drivers, and ADO.NET drivers. In simple terms, Java database connectivity is an API built especially for Java to claim access to the client database. It can update, delete, edit, and manage the client relational database via queries and commands. Even to connect with the individual databases, the API requires JDBC to establish a connection.
Steps for Connecting with JDBC
We can imply the API of JDBC to manage the tabular data saved in any relational database. Using JDBC, we can fetch and update and delete the data from the database. It is similar to Open Database Connectivity implemented by Microsoft. The user can manage the database by Java program to perform various activities like connection to the database, execution of queries, statement update to DB, a connection interface, statement interface, driver interface, prepared statement interface, retrieving the result from DB, resultset interface, callable statement interface, row set interface, metadata interface, and resultset interface. The famous class used in JDBC are the blob, clob, types, and driver manager classes.
The JDBC calls and provides the result set to the Java application. Then the database saves the data obtained from the Java application with the help of a JDBC driver. The connection object manages the connection to the database.
The major steps in JDBC to process the database connection and query execution comprises the following methods.
- Import JDBC packages
- Register and load the JDBC driver
- Set a connection to the database
- Create a statement object to execute the query
- Works on the result set
- Close the statement objects
- Close the result set
- Close the established connection
In simple terms, the connection to the JDBC interface is established in two steps.
- JDBC API supports the interaction between the JDBC manager and the Java application.
- The JDBC driver supports the communication between the JDBC manager and the database driver.
The steps to connect with the database are as follows,
- Locate or install the database which the user wants to manage or access.
- Let the JDBC library be included.
- Check that the user needs JDBC driver located on the correct classpath.
- To enter SQL commands, use the connection established.
- Once the activity is completed, close the connection.
Open a connection to the database.
The user can do a web search to get a driver for the database and JDBC. For instance, type MySQL JDBC driver will switch up a driver for MySQL. The Java-compatible database without the JDBC driver is difficult to find. Download and install SQLite, which is a very compact database. But it is not intended for production use. The user can try many things, which will be a great learning platform. It uses a file as a functional database without installing daemons or services. The file comprises both sample schema and file-based database and holds the data for further use. The user can download the SQLite sample database to start with the demo.
The relational database is a well-defined repository comprised of tables with infinite rows and columns. The adapter layer from Java to SQL is done by JDBC, which provides the Java developers to acts as a common interface to link databases, offer queries and commands, and handle the responses.
The coding should be done in IDE to import JDBC into the Java application, but it will be good if the coding is directly built-in in the text editor. Open a compatible installation of JDK for the operating system. The Java platform is developed with tools by compiling a simple Java program. The coding can be pasted by calling the file whatisJdbc.java, an in-text editor.
import java.sql.connection; // it represents the connection to the database import java.sql.drivermanager; // the data source is implied for connection pooling and obtains the association with the database. import java.sql.sqlexception; //manages the error between the database and Java application import java.sql.resultset; // it modesl the sql statement and result set. import java.sql.statement;
Then open the JDBC connection by calling the class java.sql.drivermanager via the method of getconnection(). There are three methods to open the connection with the database.
The variant takes the URL as a parameter to connect with the database. Then getconnection() with the parameter. The obtained URL is connected to the URL database, and check the documentation for the JDBC driver and database to view the format for the specific database. The URL can be viewed in H2Database. The second method is to open the connection with the database by using a password, user, and URL. Here the getconnection() obtains the user name, database URL, and password as parameters. The obtained password and user name are the user name and passwords for the database. The third method is getconnection() which takes properties and database URL as parameters. Here the properties denote the features and policies of the database.
Close the database connection
It is achieved by calling connection .close(). It is mandatory to close the database connection once the activity is completed as it consumes more resources on the application and database server.
There was a relationship between SQL and JDBC for advanced access. Though NoSQL has developed widely in the past decades, the relational database stays the same, and it is the most used datastore.
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