Design pattern to implement Database operations

I am trying to implement design pattern in my project and have been reading material over net.

we have a sales application ( in C# ) where in we are storing entities like

Customer 
Contacts
Sales Order
Lead
Opportunity

This is how i am planning to implement design pattern.

Entity would be the base class and it has common variables

namespace DesignModel.Model
{
    class Entity
    {
        protected IDBOperation dbOperation;
        public string id { get; set; }
        public int isSync { get; set; }
        public string timestamp { get; set; }

        public void insert()
        {
            dbOperation.insertData();

        }

        public void update()
        {
            dbOperation.updateData();
        }
        public void delete()
        {
            dbOperation.deleteData();

        }
    }
}

Here is the Contact class that is extending Entity class. Contact class would have its own properties too.

namespace DesignModel.Model
{
    class Contact : Entity
    {
        public Contact()
        {
             dbOperation = new DBOperations();

        }
        public string name { get; set; }
        public string company { get; set; }
        public string jobtitle { get; set; }

    }
}

Now what i have derived from the nature of this application is each entity has following operations for database interaction and to fetch data from server.

for database operation

insert
update
delete

to get and send data from server

getData
sendData

based on that i have created an interface named IDBOperation

namespace DesignModel.Database
{
    interface IDBOperation<T>
    {
        void insertData(T entity) ;
        void updateData(T entity);
        void deleteData(T entity);

        void displayData();

    }
}

and concrete class DBOperations that implements IDBOperation

namespace DesignModel.Database
{
    class DBOperations : IDBOperation<Entity>

    {

        public void insertData(Entity e) {

            Debug.WriteLine("insertData "+e.id );

        }

        public void deleteData(Entity e)
        {
            Debug.WriteLine("deleteData" + e.id);

        }

        public void updateData(Entity e)
        {
            Debug.WriteLine("updateData" + e.id);

        }
        public void displayData()
        {

        }
    }

and at last Contact class

namespace DesignModel.Model
{
    class Contact : Entity
    {
        public Contact()
        {
             dbOperation = new DBOperations();

        }
        public string name { get; set; }
        public string company { get; set; }
        public string jobtitle { get; set; }

    }
}

i am using contact as follows

    Contact contactData = new Contact();
    contactData.id = "1234";
    contactData.isSync = 1;
    contactData.jobtitle = "Sales Manger";
    contactData.insert(contactData);

I am little confused where i have been implementing it correctly or not.

the reason why i kept implementation in DBOperation because if new interface method comes i have to implement it at one place oppose to if i am implementing method in customer, contact and sales order classes.

one thing that worries me is Entity parameter in insertData inside DBOperation not sure whether i will be able to add entire contact into db or not.

so if anyone help me in providing pointers to correctly implement the design pattern in this use case then it will me more helpful