learning with head first sql query

 Learning head first query with Head_first_sql in pdf form

Comments

Post a Comment

Popular posts from this blog

SQL Tutorial with HSQLDB

Image
This assumes that you have Java setup on your machine as illustrated in the "simple" Java tutorial. Q.  Why use  HSQLB ? A.  It can be useful in a number of ways. Easy to get started and if you are a beginner, you can acquire or sharpen your SQL and database skills. It is open-sourced, hence you can use it for your self-taught projects as a database. An alternative to MySQL  database. It is used in commercial projects to write unit tests for your data access layer. Apache Derby database is another alternative. It is used in the ensuing tutorials on  JDBC  and  Hibernate  as the database. Step 1 : Download the latest version of HSQLB from   http://hsqldb.org/ . I downloaded  hsqldb-2.2.9.zip  at the time of writing and extracted zip files. The HSQLDB is unpacked under  c:\Tools  as as hown below. Step 2 : You can start the server with the following command. ? 1 c:\Tools\hsqldb-2.2.9>java -cp ./h...
Read more

Hibernate tutorial with HSQLDB

Image
This tutorial is basically an extension to the  "simple" Java  and  JDBC tutorials . Hibernate is an ORM (Object to Relational Mapping) tool. Step 1 :  First step is to bring in the relevant  Hibernate  framework jar files like  hibernate-xxx.jar ,  hibernate-annotations-xxxx.jar , and other dependent jar files that are transitively brought in from hibernate framework's pom.xml file. Here is the pom.xml file for simple Java project extended for hibernate. ? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 <project xmlns= " http://maven.apache.org/POM/4.0.0 " xmlns:xsi= " http://www.w3.org/2001/XMLSchema-instance "   xsi:schemaLocation= " http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd " >   <modelVersion...
Read more

Java Interview Questions & Answers: user defined key class

Image
This is one of my favorite core Java interview questions as not knowing this can cause subtle and intermittent issues in Java. The issues that arise from not understanding equals( ) and hashCode( ) contract can be hard to debug.    Q.  When providing a user defined key class for storing objects in a  Map (e.g. HashMap) , what methods do you have to provide or override (i.e. method overriding)? A.  You should override the  equals( ... )  and  hashCode( .. )  methods from the  Object  class. The default implementation of the  equals( ... )  and  hashCode( ... )  methods are inherited from the  java.lang.Object  class  uses an object instance’s memory location (e.g. MyObject@6c60f2ea). This can cause problems when two instances of car objects have the same color but the inherited  equals( .. )  will return false because it uses the memory location as oppose to the color, which is different ...
Read more