JIMDB (Java In Memory DataBase)

What is JIMDB?

JIMDB is a lightweight Java In Memory DataBase where you can store any Java Bean. We can perform basic SQL operations like select, insert, update, delete and etc. JIMDB is specially designed for better performance than normal SQL databases and other in memory databases. Performance can be improved by creating indexes, efficient data structures and algorithms used. It can retrieve records at time complexity of 1, from millions of records. When we handle with millions of records, performance wise JIMDB will be a good replacement of other databases.

Maven Dependency (Latest Version)

<dependency>
  <groupId>com.stanrnd.jimdb</groupId>
  <artifactId>jimdb</artifactId>
  <version>1.0-SNAPSHOT</version>
</dependency>

JIMDB Syntax with Example

Note: In the below examples, Employee class is used and the class will be look like

public class Employee {
	private String id;
	private String name;
	private String gender;
	private float salary;
	private String department;
	private String address;
	private String mailId;
	public Employee(String id, String name, String gender, float salary, String department, String address, String mailId) {
		// Initialize fields
	}
	// setters and getters

Create Table

Syntax

Table<T> table = new Table<T>(maxNoOfRecords, new IndexConfig(<field 1>, <field 2>, ...));

• T: Type of the Bean which going to be stored in Table. It can be any Java Bean class.
• maxNoOfRecords: Maximum number of beans going to be stored in Table. This can be approximate value.
• IndexConfig: IndexConfig contains whatever fields going to be used in select operations and indexes will be created for those fields.

Example

Table<Employee> table = new Table<Employee>(100, new IndexConfig("department", "address"));

Insert beans into Table

Syntax

table.insert(T);
table.insert(List<T>);

• insert(T): To insert a Bean object.
• insert(List) To insert list of bean objects.

Example

table.insert(new Employee("eid02", "Alan", "male", 20000, "HR", "Bangalore", "alan@gmail.com"));

List<Employee> list = new ArrayList<Employee>();
list.add(new Employee("eid02", "Alan", "male", 20000, "HR", "Bangalore", "alan@gmail.com"));
list.add(new Employee("eid16", "Shiny", "female", 60000, "QA", "Chennai", "shiny@gmail.com"));
list.add(new Employee("eid11", "James", "male", 50000, "IT", "Bangalore", "james@gmail.com"));
table.insert(list);

Find beans from Table

Syntax

List<T> list = table.find(new Filter(new Filter(<field 1>, Op.<any operator>, <value>), LogOp.<any operator>, new Filter(...)));

• find: Method to find bean objects from Table by passing filter criteria.
• new Filter(): This constructor accepts field name, operator and field value to match bean objects. Inner constructor to perform nested operations and will accept filter objects and logical operator.
• Op: enum to have all relational and some sql related operators.
• LogOp: enum to have all relational operators.

Example

List<Employee> employees = table.find(new Filter(new Filter(new Filter("department", Op.EQ, "IT"), LogOp.OR, new Filter("department", Op.EQ, "QA")), LogOp.AND, new Filter("address", Op.EQ, "Bangalore")));

Future Release:

• Auto Save (save the data into disk)

Note:

• Full example you can find from the above src/test/java/com/jimdb path.