prepared, callable, scrollable

Here’s a clean breakdown of Java JDBC implementations for your queries on:

1. PreparedStatements and Stored Procedures using CallableStatements

2. Scrollable and Updatable ResultSets

3. DatabaseMetadata and ResultSetMetadata

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✅ 2. PreparedStatements and Stored Procedures with CallableStatements

🔹 A. PreparedStatement Example

public void insertUsingPreparedStatement(Connection con) {
    try {
        String query = "INSERT INTO students (name, rollno, age, email) VALUES (?, ?, ?, ?)";
        PreparedStatement psmt = con.prepareStatement(query);
 
        Scanner sc = new Scanner(System.in);
        System.out.print("Name: ");
        psmt.setString(1, sc.nextLine());
 
        System.out.print("Roll No: ");
        psmt.setInt(2, Integer.parseInt(sc.nextLine()));
 
        System.out.print("Age: ");
        psmt.setInt(3, Integer.parseInt(sc.nextLine()));
 
        System.out.print("Email: ");
        psmt.setString(4, sc.nextLine());
 
        psmt.executeUpdate();
        System.out.println("Data inserted using PreparedStatement.");
    } catch (SQLException e) {
        e.printStackTrace();
    }
}

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🔹 B. CallableStatement for Stored Procedure

📌 SQL (create this in DBMS first):

DELIMITER //
CREATE PROCEDURE getStudentByRoll(IN rno INT)
BEGIN
    SELECT * FROM students WHERE rollno = rno;
END;
//
DELIMITER ;

📌 Java Code:

public void callStoredProcedure(Connection con) {
    try {
        CallableStatement cstmt = con.prepareCall("{CALL getStudentByRoll(?)}");
        Scanner sc = new Scanner(System.in);
 
        System.out.print("Enter Roll No: ");
        cstmt.setInt(1, sc.nextInt());
 
        ResultSet rs = cstmt.executeQuery();
 
        while (rs.next()) {
            System.out.println("Name: " + rs.getString("name"));
            System.out.println("Age: " + rs.getInt("age"));
            System.out.println("Email: " + rs.getString("email"));
        }
 
    } catch (SQLException e) {
        e.printStackTrace();
    }
}

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✅ 3. Scrollable and Updatable ResultSet

public void scrollAndUpdate(Connection con) {
    try {
        Statement stmt = con.createStatement(
            ResultSet.TYPE_SCROLL_SENSITIVE,
            ResultSet.CONCUR_UPDATABLE
        );
 
        ResultSet rs = stmt.executeQuery("SELECT * FROM students");
 
        // Move to last
        rs.last();
        System.out.println("Last student: " + rs.getString("name"));
 
        // Move to first
        rs.first();
        System.out.println("First student: " + rs.getString("name"));
 
        // Update age of first student
        rs.updateInt("age", rs.getInt("age") + 1);
        rs.updateRow();
        System.out.println("First student's age updated.");
 
    } catch (SQLException e) {
        e.printStackTrace();
    }
}

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✅ 4. DatabaseMetadata and ResultSetMetadata

🔹 A. DatabaseMetadata

public void printDatabaseMetadata(Connection con) {
    try {
        DatabaseMetaData dbmd = con.getMetaData();
 
        System.out.println("Database Name: " + dbmd.getDatabaseProductName());
        System.out.println("Driver Name: " + dbmd.getDriverName());
        System.out.println("URL: " + dbmd.getURL());
        System.out.println("User: " + dbmd.getUserName());
 
    } catch (SQLException e) {
        e.printStackTrace();
    }
}

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🔹 B. ResultSetMetadata

public void printResultSetMetadata(Connection con) {
    try {
        Statement stmt = con.createStatement();
        ResultSet rs = stmt.executeQuery("SELECT * FROM students");
 
        ResultSetMetaData rsmd = rs.getMetaData();
        int columnCount = rsmd.getColumnCount();
 
        System.out.println("Total columns: " + columnCount);
        for (int i = 1; i <= columnCount; i++) {
            System.out.println("Column " + i + ": " + rsmd.getColumnName(i) + " - " + rsmd.getColumnTypeName(i));
        }
 
    } catch (SQLException e) {
        e.printStackTrace();
    }
}

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