CSQL - JDBC

Jitendra Lenka Developer - Lakshya Solutions Ltd.

jitendra.lenka@lakshyasolutions.com

Module Objectives

After completing this module you will be able to :

• Understand various interfaces in JDBC.

• Write application to access CSQL database using JDBC driver.

• Understand different SQL statements executed in CSQL databse with parameter and projection value.

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The topics to be covered in this session are :-

• Introduction to CSQL main memory database.

• Overview of different Interfaces to client provided by CSQL.

• Important classes and functions for writing application in JDBC.

• Connection to the CSQL database and execute DDL and DML statements.

• Handling errors returned by various functions in JDBC.

Module Coverage

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• CSQL is a open source main memory high-performance relational database management system developed in sourceforge.net site.

• CSQL comprises suite of products such as CSQL MMDB, CSQL Cache for leading target databases such as Oracle, MySQL and Postgres , and CSQL Replication which provides high availability and load balancing cluster for MMDB.

• CSQL MMDB is 30x faster than any other leading databases with undisrupted performance for real-time applications.

• CSQL is mainly developed to be used as a cache for existing disk based commercial databases.

What is CSQL?

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• ODBCC/C++ standard interface for SQL engine.

• JDBC Java standard interface for SQL engine.

• SQLAPI Proprietary interface for SQL engine.

• DBAPIProprietary interface for Storage engine

Overview

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• Java Database Connectivity defines an API that java programs can use to connect to CSQL server.

• The JDBC API defines interfaces and classes for writing database applications in java by making database connections.

• Java application calls the JDBC library. JDBC loads a driver which talks to the CSQL database.

What is JDBC ?

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• Proprietary C++ Interface

• Important Package• java.sql

• Important classes• java.sql.Date

• java.lang.DriverManager

• java.sql.Time

• Important Interfaces• java.sql.Connection

• java.sql.PreparedStatement

• java.sql.ResultSet

• java.sql.Statement

• java.sql.SQLException

• Library• libcsqljdbc.so

JDBC

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Data Type

SQL Type Java Type

TINYINT Byte

SMALLINT Short

INTEGER Int

BIGINT Long

REAL Float

FLOAT,DOUBLE Double

CHAR java.lang.String

DATE java.sql.Date

TIME java.sql.Time

TIMESTAMP java.sql.Timestamp

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Before making a connection to database the JDBC driver should be loaded.

Class forName( <Database Driver> ) :

• Load the driver class by calling this function.• Driver class name as an argument.• Once loaded the driver class creates an instances of itself.• A client can connect to database server through JDBC driver.• The return type of this method is Class which is a class in java.lang

package.

Method for Loading Driver

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Below method will establish a connection to the database.

getConenction( <url> , <LoginName> , <password> ) :

• This method is belongs to JDBC DriverManager class.• DriverManager class defines object which can connect java application to a

JDBC driver.• Driver can recognizes the url (jdbc:csql) .• This method uses the above argument(url,LoginName, password) to

connect to database.• This method returns a new Connection object to the database.

DriverManager

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java.sql.Connection

The below methods are belongs to the Connection interface.

• Statement createStatement( ) throws SQLException.• PreparedStatement prepareStatement(<SqlStatement>) throws SQLException.

• void close( ) throws SQLException.

• void commit( ) throws SQLException.

• void rollback( ) throws SQLException.

Connection

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java.sql.Connection

In order to use DDL Statements,we require a Statement object. So, the next step is to create the Statement object from the Connection.

Statement stmt = con.createStatement()

• This method is for interacting with the database.• It generates new query plan for DDL statements.• By the help of Statement object SQL statements would be used.• A Statement object is used to send and execute SQL statements to a database.

Note : we used createStatement for DDL Statements.

Connection

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Connection

Example : Connect to the CSQL through JDBC Driver.

import java.sql.* ; public class ConnTest {

public static void main( String argv[ ] ) { Connection con = null ; try { class.forName(“csql.jdbc.JdbcSqlDriver ”) ; Connection con = DriverManager . getConnection(“jdbc:csql” , “root” ,”manager”) ; if(con==null) System.exit(1) ; con.close() ; System.exit(0) ; } catch (Exception e) { System.out.println(“Exception in Test :“ +e) ; e.getStackTrace(); System.exit(1) ;

}}

}

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java.sql.Statement

The Statement class provide the below method to execute the SQL statements, mainly for DDL Statements.

execute(<sqlstatement>)

• This method is for execution of SQL statements in the database.• Returns a result set object using specified Statement object.• Return type is Boolean value.

Note : execute method for DDL statements.

Execution of DDL Statements

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Example : CREATE TABLE EMP(eid integer, ename char(20));

CREATE INDEX IDX_EMP ON EMP(eid);

// Driver should be register here followed by Connection.

Statement cStmt = con . createStatement();

cStmt . execute( “CREATE TABLE EMP(eid integer, ename char(20)) ;” ) ;cStmt . execute( “CREATE INDEX IDX_EMP ON EMP(eid) ;” ) ;cStmt.close();

con.commit();con.close() ;

// close the connection.

Create Table and Index

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java.sql.PreparedStatement

The PreparedStatement Interface provides the below methods to execute the SQL statements, for DML Statements.

• ResultSet executeQuery()

execute the select statements in the database.

• int execute Update()

This method is used for UPDATE,DELETE,INSERT statements.

• Xxx setXxx()

Used for input value of parameter marker for different data types.

• void close()

It implicitly closes all PreparedStatement and Statement instances associated with the connection.

Methods for DML Statements

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The below method will execute precompiled SQL query with or without parameters.

PreparedStatement stmt = con . prepareStatement( String sql )

- This method generates one time query plan.

- This method is called by connection object.

- Argument is sql statement.

- It returns the new PreparedStatement object.

Methods for DML Statements

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In order to bind the input parameters, PreparedStatements provides the below methods to set the IN parameters

• setInt( Index, Integer )• setString( Index, String )

- The binding of an variable in positional based.

- The first parameter is the index of the column to set for both the methods.

- The second parameter is the value according to the datatypes.

Binding the Parameters

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Example : INSERT INTO EMP(eid, ename) VALUES( ?, ?) ;

// Register the driver and get the connection object.// create the prepared Statement object.

PreparedStatement stmt =nul ;stmt =con.prepareStatement( “ INSERT INTO EMP(eid,ename) VALUES(?,?) ;”) ;

for( int i=0; i<5 ;i++ ) {

stmt . setInt(1, i) ;stmt.setString( 2 , String.valueOf( i+100 )) ;ret = stmt . executeUpdate();if(ret !=1) break ; count++;

}stmt.close();con . commit() ;con . close() ;

Table - Insert

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Example : UPDATE EMP SET ename = ? WHERE eid = ? ;

// you register the driver and get the connection object.// create the prepared Statement object.

PreparedStatement stmt = nul ;stmt=con.prepareStatement(“UPDATE EMP SET ename=? Where eid=? ;”) ;

for( int i=0; i<5 ;i++ ) {

stmt.setString( 1 , String.valueOf( i+200 )) ;stmt.setInt(2,i) ;ret = stmt . executeUpdate();if(ret !=1) break ; count++;

}stmt.close();con . commit() ;con . close() ;

Table - Update

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The below method is used for executing sql statements and reading the values.

ResultSet executeQuery( ) - This method is belongs to Statement Interface- It executes select statements in the database.- This returns a result set object using the specified statement or prepared statement object and SQL SELECT statement .

Java.sql.ResultSet boolean next( ) - This method is belongs to ResultSet interface

- The iterator is initialized to a position before the first row.- This method will be called once to move it to the first row.

xxx getXxx ( int column number ) - once we have the result set we can retrieve the data by looping through it.

void close ( )- used to close a result set.

Executing Query

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Example : SELECT * FROM EMP WHERE eid = ? ;

// Register the driver and get the connection object.

// Create the statement object.

PreparedStatement selStmt = null ; int count =0 , ret = 0 ;selStmt = con . prepareStatement (SELECT * FROM EMP WHERE eid = ? ; ”) ;ResultSet rs = null ;for ( int i = 0 ; i < 5 ; i++ ){ selStmt . setInt ( 1 , i ) ; ret = selStmt . executeQuery( ) ; while ( rs . next( ) ) {

System.out.println ( “ value = rs . getInt( 1 ) + “ “ + rs . getString( 2 ) ) ;count ++ ;

} rs . close ( ) ;}

Table – Select - Where

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Example : DELETE FROM EMP WHERE eid = ? ;

// Register the driver and get the connection object.

// create the statement object.

PreparedStatement stmt = null ; int count =0;stmt = con . prepareStatement ( “ DELETE FROM EMP WHERE eid = ? ; “ ) ;for ( int i =0 ; i < 5 ; i++ ){ stmt . setInt ( 1 , i) ; ret = stmt . executeUpdate( ) ; if( ret !=1 ) break ; count ++ ;}stmt . Close ( ) ;

con . Commit ( ) ; con . Close ( ) ;

Table – Delete

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Example : DROP TABLE EMP ;

import java . Sql . * ;public class jdbcexample {

public static void main ( String [ ] args ) { try { // get the connection object ‘ con ‘

Statement cStmt = con . createStatement ( ) ;cStmt . execute ( “ DROP TABLE EMP ; “ ) ;cStmt . Close ( ) ;con . Close ( ) ;

} catch ( Exception e ) { // print the error value here

}}

}

Table – Drop

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Example : set the auto commit false and commit the transaction.

import java.sql.* ; public class ConnTest {

public static void main( String argv[ ] ) { Connection con = null ; try {

class.forName(“csql.jdbc.JdbcSqlDriver ”) ; Connection con = DriverManager . getConnection(“jdbc:csql” ,

“root” ,”manager”) ; con . setAutoCommit(false) ;

// perform DML operations here

con.commit() ;

}// close the connection

Transaction

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Referenced Manuals:

User Manual: Describes Concept, components and basic usages and useful for administrators.

Programmer Guide: It covers JDBC, ODBC and proprietary SQL interface and useful for application developers.

Cache Guide: Describes caching functionality of CSQL and configuration settings required to set up caching for MySQL, Postgres and Oracle

DBMS.

DOWNLOAD: http://www.csqldb.com/pro_documentation.html

CSQL Documents

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For detailed information, please visit:

Enterprise: www.csqldb.comOpen Source: http://sourceforge.net/products/csql

CSQL Web Site

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