Difference between revisions of "Java Database Connectivity (JDBC)"
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− | Java Database Connectivity (JDBC) | + | == What is Java Database Connectivity (JDBC)? == |
+ | |||
+ | '''Java Database Connectivity (JDBC)''' is a Java-based data access technology that enables Java applications to connect to relational databases. It consists of a set of classes and interfaces that provide a standard API for establishing a connection to a database and executing SQL statements. | ||
+ | |||
+ | JDBC provides a standardized API for interacting with a database, regardless of the database vendor or type. This means that the same JDBC code can be used to connect to different databases, as long as there is a JDBC driver available for that database. | ||
+ | |||
+ | To use JDBC, you must first download and install a JDBC driver for the database you want to connect to. Then, you can use the JDBC API to create a connection to the database, send SQL statements, and process the results. | ||
+ | |||
+ | Here's a simple example of how to use JDBC to connect to a database and execute a SELECT statement: | ||
+ | |||
+ | |||
+ | import java.sql.*; | ||
+ | |||
+ | public class JDBCExample { | ||
+ | static final String JDBC_DRIVER = "com.mysql.jdbc.Driver"; | ||
+ | static final String DB_URL = "jdbc:mysql://localhost/test"; | ||
+ | |||
+ | static final String USER = "username"; | ||
+ | static final String PASS = "password"; | ||
+ | |||
+ | public static void main(String[] args) { | ||
+ | Connection conn = null; | ||
+ | Statement stmt = null; | ||
+ | try{ | ||
+ | Class.forName("com.mysql.jdbc.Driver"); | ||
+ | |||
+ | System.out.println("Connecting to database..."); | ||
+ | conn = DriverManager.getConnection(DB_URL,USER,PASS); | ||
+ | |||
+ | System.out.println("Creating statement..."); | ||
+ | stmt = conn.createStatement(); | ||
+ | String sql; | ||
+ | sql = "SELECT id, first, last, age FROM Employees"; | ||
+ | ResultSet rs = stmt.executeQuery(sql); | ||
+ | |||
+ | while(rs.next()){ | ||
+ | int id = rs.getInt("id"); | ||
+ | int age = rs.getInt("age"); | ||
+ | String first = rs.getString("first"); | ||
+ | String last = rs.getString("last"); | ||
+ | |||
+ | System.out.print("ID: " + id); | ||
+ | System.out.print(", Age: " + age); | ||
+ | System.out.print(", First: " + first); | ||
+ | System.out.println(", Last: " + last); | ||
+ | } | ||
+ | rs.close(); | ||
+ | stmt.close(); | ||
+ | conn.close(); | ||
+ | }catch(SQLException se){ | ||
+ | se.printStackTrace(); | ||
+ | }catch(Exception e){ | ||
+ | e.printStackTrace(); | ||
+ | }finally{ | ||
+ | try{ | ||
+ | if(stmt!=null) | ||
+ | stmt.close(); | ||
+ | }catch(SQLException se2){ | ||
+ | } | ||
+ | try{ | ||
+ | if(conn!=null) | ||
+ | conn.close(); | ||
+ | }catch(SQLException se){ | ||
+ | se.printStackTrace(); | ||
+ | } | ||
+ | } | ||
+ | System.out.println("Goodbye!"); | ||
+ | } | ||
+ | |||
+ | |||
+ | |||
+ | |||
+ | |||
+ | |||
+ | ==See Also== | ||
+ | *[[Open Database Connectivity (ODBC)]] | ||
+ | |||
+ | |||
+ | |||
+ | |||
+ | |||
+ | ==References== | ||
+ | <references /> |
Latest revision as of 11:40, 7 January 2023
What is Java Database Connectivity (JDBC)?
Java Database Connectivity (JDBC) is a Java-based data access technology that enables Java applications to connect to relational databases. It consists of a set of classes and interfaces that provide a standard API for establishing a connection to a database and executing SQL statements.
JDBC provides a standardized API for interacting with a database, regardless of the database vendor or type. This means that the same JDBC code can be used to connect to different databases, as long as there is a JDBC driver available for that database.
To use JDBC, you must first download and install a JDBC driver for the database you want to connect to. Then, you can use the JDBC API to create a connection to the database, send SQL statements, and process the results.
Here's a simple example of how to use JDBC to connect to a database and execute a SELECT statement:
import java.sql.*;
public class JDBCExample {
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver"; static final String DB_URL = "jdbc:mysql://localhost/test";
static final String USER = "username"; static final String PASS = "password"; public static void main(String[] args) { Connection conn = null; Statement stmt = null; try{ Class.forName("com.mysql.jdbc.Driver");
System.out.println("Connecting to database..."); conn = DriverManager.getConnection(DB_URL,USER,PASS);
System.out.println("Creating statement..."); stmt = conn.createStatement(); String sql; sql = "SELECT id, first, last, age FROM Employees"; ResultSet rs = stmt.executeQuery(sql);
while(rs.next()){ int id = rs.getInt("id"); int age = rs.getInt("age"); String first = rs.getString("first"); String last = rs.getString("last");
System.out.print("ID: " + id); System.out.print(", Age: " + age); System.out.print(", First: " + first); System.out.println(", Last: " + last); } rs.close(); stmt.close(); conn.close(); }catch(SQLException se){ se.printStackTrace(); }catch(Exception e){ e.printStackTrace(); }finally{ try{ if(stmt!=null) stmt.close(); }catch(SQLException se2){ } try{ if(conn!=null) conn.close(); }catch(SQLException se){ se.printStackTrace(); } } System.out.println("Goodbye!");
}
See Also