Java Program to Delete a Column in a Table Using JDBC - GeeksforGeeks

14 Aug, 2021
Before deleting a column in a table, first is need to connect the java application to the database. Java has its own API which JDBC API which uses JDBC drivers for database connections. Before JDBC, ODBC API was used but it was written in C which means it was platform-dependent. JDBC API provides the applications to JDBC connection and JDBC driver provides manager to driver connection. 
Algorithm: Always remember these 7 thumb golden steps to deal with JDBC in order to deal with the database and between App(Main) class and connection class of it.
Importing the databaseRegistering the Java classEstablishing a connectionCreating a statementExecuting the queryProcess the resultsClosing connection
Importing the database
Registering the Java class
Establishing a connection
Creating a statement
Executing the query
Process the results
Closing connection
Procedure: to delete a column in a table from the database created using JDBC is as follows:
Step 1: Loading “mysqlconnector.jar” in the program.
Step 2: Creating a database and adding a table with records 
Using MySQL‘cmd’ DriverDriverManager()Connection()Statement()Resultset() which the classes provided by JDBC API
‘cmd’ Driver
DriverManager()
Connection()
Statement()
Resultset() which the classes provided by JDBC API
Further 5 steps are demonstrated in the java program. (App class or Main class) of the Connection class.
Implementation: Java program using JDBC to delete a Column in a Table
Java
// Java program using  JDBC to// Delete a Column in a Table // Step 1: Importing database filesimport java.sql.*; public class GFG {     // URL that points to mysql database    // DB stands for database    static final String url        = "jdbc:mysql://localhost:3306/db";     // Main driver method    public static void main(String[] args) throws ClassNotFoundException    {         // Try block to check exceptions        try {             // Step 2: Load and Register drivers             // Class.forName() method is user for            // driver registration with name of the driver            // as argument that used MySQL driver            Class.forName("com.mysql.jdbc.Driver");             // Step 3: Create a connection             // getConnection() establishes a connection            // It takes url that points to your database            // username and password of MySQL connections as            // arguments            Connection conn = DriverManager.getConnection(                url, "root", "1234");             // create.Statement() creates statement object            // which is responsible for executing queries on            // table            Statement stmt = conn.createStatement();             // Executing the query student is the table            // name & address is column             // Step 4: Create a statement            String query                = "ALTER TABLE student Drop address";             // Step 5: Execute the query             // executeUpdate() returns number of rows            // affected by the execution of the statement            int result = stmt.executeUpdate(query);             // Step 6: Process the results             // if result is greater than 0            // it means values has been added            if (result > 0)                System.out.println(                    "A column from the table is deleted.");            else                System.out.println("unsuccessful deletion ");             // Step 7: Closing connection            conn.close();        }         // Catch block to handle exceptions        catch (SQLException e) {             // Print the exception            System.out.println(e);        }    }}
Output:
akshaysingh98088
sooda367
JDBC
Picked
Technical Scripter 2020
Java
Java Programs
Technical Scripter
Java
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Comments
Old Comments
Constructors in Java
Stream In Java
Exceptions in Java
Different ways of Reading a text file in Java
Functional Interfaces in Java
Convert a String to Character array in Java
Java Programming Examples
Convert Double to Integer in Java
Implementing a Linked List in Java using Class
How to Iterate HashMap in Java?