JsonFileDataBase 1.0.2

JsonFileDataBase

version 1.0.2

See Sample Code See GitHub Repository

vNext: support simple relations

The following is a demo fo use of JsonFileDataBase in a C# web project

Create the data model

Your model classes should implement ITable interface and thus must contain the Id propoerty.

    public class Person : ITable
    {
        public int Id { get; set; }
        //add other propoerties
    }

    public class Location :ITable
    {
        public int Id { get; set; }
        //add other propoerties
    }

Create the Database Context

The main class that coordinates JsonFileDataBase functionality for a given data model is the database context class. You create this class by deriving from the JsonFileDB.DbContext class. In your code you specify which entities are included in the data model.

The DBContext constructor requires a string of the path to the JSON file to be used as database.

    public AppDBContext() 
    :base("jsonFilePath") //can be provided as string literal
    {

    }

OR alternatively The path can be set in the app setting file and injected from configuration service using dependancy injection

    public AppDBContext(IConfiguration configuration) 
    :base(configuration.GetConnectionString("JSONFilePath")) 
    {

    }

Add the Models in the Database context: regester the classes as tables

    public class AppDBContext : DBContext
    { 
        public AppDBContext() 
        :base("jsonFilePath") //can be provided as string literal
        {
        }
        //declare all table intstances
        public Dataset<Person> Persons { get; set; }
        public Dataset<Location> Locations { get; set; }
    }

This code creates a DbSet property for each entity set. In JsonFileDataBase terminology, an entity set typically corresponds to a database table, and an entity corresponds to a row in the table.

Finally, initialize the Dataset (table) instances in the database; this generates the tables only once and if the don't exist.

    public AppDBContext() 
    :base("") 
    {
        Persons = new Dataset<Person>(_database);
        Locations = new Dataset<Location>(_database);
    }

The final code should look similar to this:

    public class AppDBContext : DBContext
    { 
        public AppDBContext() 
        :base("jsonFilePath") //can be provided as string literal
        {
            Persons = new Dataset<Person>(_database);
            Locations = new Dataset<Location>(_database);
        }
        //declare all table intstances
        public Dataset<Person> Persons { get; set; }
        public Dataset<Location> Locations { get; set; }
    }

When the database is created, JsonFileDataBase creates tables that have names the same as the Model class names all in lowercase.

Register the context with dependency injection

ASP.NET Core implements dependency injection by default. Services (such as the JsonFileDataBase database context) are registered with dependency injection during application startup. Components that require these services (such as MVC controllers) are provided these services via constructor parameters.

To register AppDBContext as a service, open Startup.cs, and add the services.AddSingleton<IDBContext, AppDBContext>(); line to the ConfigureServices method.

    public void ConfigureServices(IServiceCollection services
    {       
        services.AddSingleton<IDBContext, AppDBContext>();
        services.AddMvc();
    }

Register the DBContext in the controler class

    public class PersonController : Controller
    {
        private AppDBContext _db;

        public PersonController(IDBContext db)
        {
            _db = (AppDBContext) db;
        }
    }

From here the Database CRUD operation can be achieved

Example:

    _db.Persons.Add(person); //add person to database
    _db.Persons.GetAll();    //get all entities from the person table
    _db.Persons.GetAllAsync();    //get all entities from the person table asyncronously
    _db.Persons.Find(id);   //find a person with a specific id from the person table
    _db.Persons.Findasync(id);   //find a person with a specific id from the person table asyncronously
    _db.Persons.Remove(id);  //remos the person with a specified id from the person table
    _db.Persons.Update(person); //updates the person

Save changes to database after Add(), Remove(), and Update() function call.

 _db.SaveChanges();       //saves changes to database

See Sample Code