Why Role Preparedstatement Inwards Coffee Jdbc – Illustration Tutorial

PreparedStatement inwards Java is i of several ways to execute SQL queries using JDBC API. Java provides Statement,

PreparedStatement in addition to CallableStatement for executing queries. Out of these three, Statement is used for full general purpose queries, PreparedStatement is used for executing parametric query in addition to CallableStatement is used for executing Stored Procedures. PreparedStatement is every bit good a pop theme inwards coffee interviews. Questions similar Difference betwixt Statement in addition to PreparedStatement inwards Java in addition to How to preclude SQL Injection attacks inwards Java are popular coffee interview questions. In this Java JDBC tutorial nosotros volition come across why should you lot utilization apply PreparedStatement inwards Java, What are the major advantages of using PreparedStatement inwards Java in addition to how PreparedStatement prevents SQL Injection attacks inwards Java.

This article is inwards continuation of my before ship service on database in addition to coffee similar 4 tips to improve functioning of Java application amongst database in addition to Difference betwixt truncate in addition to delete inwards SQL.If you lot haven’t read  them already you lot may found  those tutorial useful in addition to interesting.

What is PreparedStatement inwards Java

PreparedStatement is a shape inwards java.sql bundle in addition to allows Java programmer to execute SQL queries past times using JDBC package. You tin larn PreparedStatement object past times calling connection.prepareStatement() method.SQL queries passed to this method goes to Database for pre-compilation if JDBC driver supports it. If it doesn't than pre-compilation occurs when you lot execute prepared queries. Prepared Statement queries are pre-compiled on database in addition to at that topographic point access invention volition live on reused to execute farther queries which allows them to execute much quicker than normal queries generated past times Statement object. Here is an example of how to utilization PreparedStatement inwards Java:

public class PreparedStmtExample {

    public static void main(String args[]) throws SQLException {
        Connection conn = DriverManager.getConnection("mysql:\\localhost:1520", "root", "root");
        PreparedStatement preStatement = conn.prepareStatement("select distinct loan_type from loan where bank=?");
        preStatement.setString(1, "Citibank");
   
        ResultSet effect = preStatement.executeQuery();
     
        while(result.next()){
            System.out.println("Loan Type: " + result.getString("loan_type"));
        }      
    }
} 
Output:
Loan Type: Personal Loan
Loan Type: Auto Loan
Loan Type: Home Loan
Loan Type: Gold Loan

In this representative of PreparedStatement same query in addition to access path volition live on used if you lot transcend a dissimilar parameter  e.g.

"Standard Charted" or "HSBC". ResultSet returned past times prepared disputation execution is of "TYPE_FORWARD_ONLY" only tin live on customized past times using overloaded method of prepareStatement().

Benefits of Java Prepared Statement

PreparedStatement inwards Java JDBC offers several benefits in addition to it’s a recommended agency to execute SQL queries inwards whatever corporation Java application or inwards production code. Here are few advantages of using PreparedStatement in Java:

1. PreparedStatement allows you lot to write dynamic in addition to parametric query.

By using PreparedStatement inwards Java you lot tin write parametrized sql queries in addition to ship dissimilar parameters past times using same sql queries which is lot ameliorate than creating dissimilar queries. Here is an representative of parametric query written using PreparedStatement inwards java:

select interest_rate from loan where loan_type=?

Now you lot tin run this query for whatever loan type e.g. "personal loan”, "home loan" or "gold loan". This example of SELECT query is called parametric or parametrized query because it tin live on invoked amongst dissimilar parameter. Here “?” is used every bit identify holder for parameter.

2. PreparedStatement is faster than Statement inwards Java

One of the major benefits of using PreparedStatement is ameliorate performance. PreparedStatement gets pre compiled

In database in addition to at that topographic point access invention is every bit good cached inwards database, which allows database to execute parametric query written using prepared disputation much faster than normal query because it has less function to do. You should ever endeavour to utilization PreparedStatement inwards production JDBC code to cut charge on database. In guild to larn functioning exercise goodness its worth noting to use exclusively parametrized version of sql query in addition to non amongst string concatenation. Out of next 2 examples of SELECT queries, get-go representative of SELECT query  volition non offering whatever functioning benefit:

SQL Query 1: PreparedStatement amongst String concatenation

String loanType = getLoanType();
PreparedStatement prestmt = conn.prepareStatement("select banks from loan where loan_type=" + loanType);

SQL Query 2: Parameterized query using PreparedStatement

PreparedStatement prestmt = conn.prepareStatement("select banks from loan where loan_type=?");
prestmt.setString(1,loanType);

Second SQL query is right utilization of PreparedStatement inwards Java in addition to give ameliorate functioning than SQL query1.

3. PreparedStatement prevents SQL Injection attacks inwards Java

If you lot accept been working inwards Java spider web application you lot must live on familiar amongst infamous SQL Injection attacks, final twelvemonth Sony got victim of SQL injection in addition to compromised several Sony play station user data. In SQL Injection attack, malicious user transcend SQL meta-data combined amongst input which allowed them to execute sql query of at that topographic point choice, If non validated or prevented before sending query to database. By using parametric queries in addition to PreparedStatement you lot preclude many forms of SQL injection because all the parameters passed every bit purpose of place-holder volition live on escaped automatically past times JDBC Driver. Though It’s worth remembering that inwards in a higher identify representative of 2 PreparedStatement exclusively instant representative volition preclude SQL injection attacks in addition to get-go representative is non secure amongst SQL injection.

4. At final PreparedStatement queries are to a greater extent than readable in addition to secure than cluttered string concatenated queries.

Limitation of Java PreparedStatement

Despite of existence rattling useful PreparedStatement also has few limitations:

1. In guild to preclude SQL Injection attacks inwards Java, PreparedStatement doesn't allow multiple values for i placeholder (?) who makes it tricky to execute SQL query amongst IN clause. Following representative of SQL query amongst IN clause using prepared Statement volition non function inwards Java:

select * from loan where loan_type IN ( ?)
preparedSatement.setString(1, "'personal loan', 'home loan', 'gold loan'");

Though at that topographic point are around workarounds in addition to ways to execute IN queries using PreparedStatement only those are

rather tricky or accept functioning impact.

Important points on PreparedStatement inwards Java

Here are few of import points most PreparedStatement Class inwards Java, worth remembering:

1. PreparedStatement inwards Java allows you lot to write parametrized query which gives ameliorate functioning than Statement class inwards Java.

2. In instance of PreparedStatement, Database utilization an already compiled in addition to defined access plan, this allows prepared disputation query to run faster than normal query.

3. Parametrized query written using PreparedStatement inwards Java prevents many mutual SQL Injection attacks.

4. PreparedStatement allows you lot to write dynamic query inwards Java.

5. PreparedStatement are associated amongst java.sql.Connection object, i time you lot driblet a connectedness all PreparedStatement  associated amongst that connectedness volition live on dropped past times Database.

6. "?" is every bit good called placeholder or IN parameter inwards Java.

7. PreparedStatement query render FORWARD_ONLY ResultSet, then you lot tin exclusively motion inwards i direction Also concurrency score of ResultSet would live on "CONCUR_READ_ONLY".

8. All JDBC Driver doesn't back upwardly pre compilation of SQL query inwards that instance query is non sent to database when you lot telephone phone prepareStatement(..) method instead they would live on sent to database when you lot execute PreparedStatement query.

9. Index of placeholder or parameter starts amongst "1" in addition to non amongst "0", which is mutual crusade of java.sql.SQLException: Invalid column index . So inwards a PreparedStatement t of 2 placeholder, get-go volition live on referred past times index 1 in addition to instant volition live on reference past times index 2.

These were the reasons Why PreparedStatement in coffee is rattling pop in addition to useful. You tin withal utilization Statement object for show programmers only regard PreparedStatement before moving to production.

Further Learning
JSP, Servlets in addition to JDBC for Beginners: Build a Database App
Complete JDBC Programming Part 1 in addition to 2
10 versatile examples of Enum inwards Java

Beginners guide to Generics inwards Java

How to utilization Factory blueprint pattern inwards Java amongst Example

10 Interview questions on Singleton inwards Java

How to create out transaction inwards database

How to utilization mysqldump utility for db backup

Why Java doesn’t back upwardly multiple inheritance

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