You should use of microsoft.sharepoint for access data into a datatable for easy calling by using this below class. 

Method for calling into Database :  

DataTable x = new DataTable(); 
x = ClassName.GetList("http://your site URL", "List table name");

Fetching data in DB from console application and create a new new list item by this below code : 

Clientdata data = new Clientdata Data("http://SiteUrl");  
//list name "mindstick"

List mindstickList = data.Web.Lists.GetByTitle("mindstick"); 

// creating a regular list item

ListItemCreationInformation itemCreateInfo = new ListItemCreationInformation(); 

ListItem newItem = mindstickList.AddItem(itemCreateInfo); 

newItem["Title"] = "Unleash your Imagination"; 

newItem["Body"] = "Software Development"; 

newItem.Update(); 

mindstick.ExecuteQuery();  

I hope ,It would be helpful for you..

Happy Coding :)