KingKiller_p1

Basic ORM based on Hibernate with some django influence

Simple implementation

• add the required dependency below to your projects POM file
• create a configuration file to point towards your database like the example shown
• create a mapping file for any objects you wish to map to a given table in your database
• add the required setup lines in your code and use as shown below!

Simple setup in code to get you connected to a database and up and running with CRUD functions

//get user object map file once for all instances of the application
static Mapper mapper = new Mapper("src/main/resources/KingKiller.cfg.xml");
//create sessions to pull from every time this class gets instanciated in the app
static SessionManager allSessions = mapper.getSessionManager();
//use the instance session to call sql commands etc.
private Session dbSession;

//create objects to replicate
this.eric = new Employee(); 
eric.setFirstName("Eric");
this.newman = new Employee();
newman.setFirstName("Newman");

dbSession.create(eric); // ----> this creates a new entry in the mapped employee table with first name eric and default values for the class elsewhere

List<Employee> queryRead = 
(List<Employee>) dbSession.readAll(eric); // ----> this reads all the entries in the mapped table

List<Employee> queryRead = 
(List<Employee>) dbSession.findByField(eric, firstName); // ----> this finds all entries in the mapped table matching the passed objects params    

dbSession.update(newman, eric); // ----> this updates a target entry (eric in this case) with a source entry in the mapped class table
    
dbSession.delete(newman); // ----> this deletes a table entry matching the fields in the eric object from the mapped employee class table
    

Sample configuration file - the location of this file needs to be passed to the initial mapper object

<configuration>
    <dbConfig>
        <url>jdbc:postgresql://somedb.cdsasdf.us-east-2.rds.amazonaws.com:5432/mydb</url>
        <username>databaseusername</username>
        <password>databasepassword</password>
    </dbConfig>
</configuration>

Sample mapping file - xml file that represents the object-table relationships

<?xml version = "1.0" encoding = "utf-8"?>

<map>
    <class>
        <name>Account</name>
        <tablename>Accounts</tablename>
        <column>
            <objfieldname>id</objfieldname>
            <colname>account_id</colname>
            <type>int</type>
        </column>
        <column>
            <objfieldname>userId</objfieldname>
            <colname>user_id</colname>
            <type>int</type>
        </column>
        <column>
            <objfieldname>balance</objfieldname>
            <colname>balance</colname>
            <type>double</type>
        </column>
    </class>
</map>

Sample pom file entry to include project as dependency

<dependency>
    <groupId>com.revature</groupId>
    <artifactId>KingKiller</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

Goals Achieved:

• Connection pooling to increase speed of application after loadup - ie hand out an already active connection each time new session created
• Can handle int, double, string etc. Can handle BigDecimal that comes from big doubles from the sql database.
• Create works
• Read works in a variety of ways - can read specific entries, specific columns and whole tables
• Update is pretty simple but allows us to replace a record in the database with an object by specifying the target record through an object with matching fields
  • IE you instantiate an object to the field values your targetting, then you instantiate a copy and change whatever field you want edited in the db and call update
• Delete works
• Uses XML to map objects to the correct tables in the databse and to provide the correct column names in reference to the object field names
• Uses XML to map db configuration object
• JUNIT testing was pretty basic but successful and REALLY helpful
• Integrated into the bank app create and read by fields. The create is used to create accounts and users and the read by field is used for login verification and account retrieval.
• Javadocs generated and useful for understanding application

WishList:

• Implementation to handle annotation based mapping based on user preference
• Table joins and creation
• Major refactor of scraper, dbdao/dbservice, and request generator as well as a review of the mapper/sessionmanager relationship
• Log4J implemented
• General restructuring of some of the types passed around (go from List to ArrayList bit too much) and also fully fleshed out columnfield, primarykey etc objects.