week 2 unit 3 - sap

Week 2 Unit 3:

Creating a JDBC Application

January, 2015

2 Public © 2014 SAP SE or an SAP affiliate company. All rights reserved.

Creating a JDBC Application JDBC Overview

Java Database Connectivity (JDBC)

Java-based data access technology

Defines how a client can connect,

query, and update data in a database

JDBC API

JDBC connections support creation and

execution of statements

ResultSet presents the outcome after a

statement has been executed


Creating a JDBC Application Why Use JDBC?

Advantages of JDBC

Clean and easy for small applications

Good performance with large amounts

of data

Allows optimization of SQL requests

Reuse of existing JDBC libraries

(Liquibase, Hibernate)

Disadvantages of JDBC

Large programming overhead for large

projects

Concurrency support and transaction

and connection management required

Initial creation of database structures

required


Creating a JDBC Application JDBC Sample

Uses standard database access

(JDBC)

Needs only a Web container, so can

run in both runtimes

Java Web (1.x)

Java EE 6 Web Profile (2.x)

PersistenceWithEJBServlet

PersonDAO

Person

Web Container

Java EE 6 Web Profile (2.x) or

Java Web (1.x)

Schemas

DB

JDBC



Import to Eclipse as

‘Existing Projects into Workspace’

Location:

<SDK_path>\samples\persistence-with-jdbc



Building Blocks:

Person.java

holds the information for a person

PersonDAO.java

performs all operations with DB

PersistenceWithJDBCServlet.java

provides interaction with the end users and

looks up the DataSource from JNDI

web.xml

web application descriptor; defines

datasource resource



Run the sample

– ‘Run on Server’

Configure SAP HANA Cloud Server

– hanatrial.ondemand.com

Request URL

– https://<application_name><account_name>.

hanatrial.ondemand.com/persistence-with-

jdbc/



In the background:

A new schema is created

Schema is bound to the application

When app requests data source the app

gets connected to this schema

– Maximum 8 parallel database connections per

schema

When application is undeployed, the

schema is not removed

When application is redeployed, it uses

same schema and bindings


Creating a JDBC Application How Can I See the SQL Statements Sent to the Database?

SQL Trace

Provides a log of selected SQL

statements

Relevant for both JPA and JDBC

applications

Integrated in the standard trace log

files

Disabled by default

Scenarios

Investigate database access-related

performance issues

Determine inefficient SQL statements


Creating a JDBC Application How to Enable the SQL Trace

Set the log level of “com.sap.core.persistence.sql.trace” to DEBUG

Tools:

Eclipse IDE

SAP HANA Cloud Platform Cockpit


Creating a JDBC Application How to Read SQL Trace Records

The SQL trace is written in the default trace log file

File name prefix ljs_trace_vsa

Tools:

Eclipse IDE

SAP HANA Cloud Platform Cockpit


Creating a JDBC Application What You’ve Learned in This Unit

What JDBC is

The advantages and disadvantages

of JDBC

What a persistence-enabled JDBC

application looks like

What happens in the background

when an application is deployed and

started

How to trace the SQL statements

performed by your application

How to enable, disable, and display

the SQL trace recordings

Contact information:

[email protected]


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