C# ORM example application
The following tutorial implements a REST API server using the Entity Framework ORM. The scenario is that of an e-commerce application where database access is managed using the Entity Framework Core.
The source for the above application can be found in the Using ORMs with YugabyteDB repository.
Prerequisites
This tutorial assumes that you have:
- YugabyteDB up and running. Download and install YugabyteDB by following the steps in Quick start.
- .NET SDK 6.0 or later.
Clone the "orm-examples" repository
$ git clone https://github.com/YugabyteDB-Samples/orm-examples.git && cd orm-examples/csharp/entityframework
Set up the database connection
To modify the database connection settings, change the default ConnectionStrings
in appsettings.json
file which is in the following format:
Host=$hostName; Port=$dbPort; Username=$dbUser; Password=$dbPassword; Database=$database
Properties | Description | Default |
---|---|---|
Host | Database server IP address or DNS name. | 127.0.0.1 |
Port | Database port where it accepts client connections. | 5433 |
Username | The username to connect to the database. | yugabyte |
Password | The password to connect to the database. | yugabyte |
Database | Database instance in database server. | ysql_entityframework |
Start the REST API server
To change default port for REST API Server, go to Properties/launchSettings.json
and change the applicationUrl
field.
-
Build the REST API server.
$ dotnet build
-
Run the REST API server
$ dotnet run
The REST server will run at http://localhost:8080
by default.
Send requests to the application
Create 2 users.
$ curl --data '{ "firstName" : "John", "lastName" : "Smith", "email" : "jsmith@example.com" }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/users
$ curl --data '{ "firstName" : "Tom", "lastName" : "Stewart", "email" : "tstewart@example.com" }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/users
Create 2 products.
$ curl \
--data '{ "productName": "Notebook", "description": "200 page notebook", "price": 7.50 }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/products
$ curl \
--data '{ "productName": "Pencil", "description": "Mechanical pencil", "price": 2.50 }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/products
Verify the userId
and productId
from the database using the following YSQL commands.
yugabyte=# \c ysql_entityframework
You are now connected to database "ysql_entityframework" as user "yugabyte".
ysql_entityframework=# SELECT * FROM users;
user_id | first_name | last_name | user_email
---------+------------+-----------+----------------------
1 | John | Smith | jsmith@example.com
101 | Tom | Stewart | tstewart@example.com
(2 rows)
ysql_entityframework=# SELECT * FROM products;
product_id | description | price | product_name
------------+-------------------+-------+--------------
1 | 200 page notebook | 7.50 | Notebook
101 | Mechanical pencil | 2.50 | Pencil
(2 rows)
Create 2 orders with products using the userId
for John.
$ curl \
--data '{ "userId": "1", "products": [ { "productId": 1, "units": 2 } ] }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/orders
$ curl \
--data '{ "userId": "1", "products": [ { "productId": 1, "units": 2 }, { "productId": 101, "units": 4 } ] }' \
-v -X POST -H 'Content-Type:application/json' http://localhost:8080/orders
Query results
Use the YSQL shell
ysql_entityframework=# SELECT count(*) FROM users;
count
-------
2
(1 row)
ysql_entityframework=# SELECT count(*) FROM products;
count
-------
2
(1 row)
ysql_entityframework=# SELECT count(*) FROM orders;
count
-------
2
(1 row)
Use the REST API
To use the REST API server to verify that the users, products, and orders were created in the ysql_entityframework
database, enter the following commands. The results are output in JSON format.
$ curl http://localhost:8080/users
{
"content": [
{
"userId": 101,
"firstName": "Tom",
"lastName": "Stewart",
"email": "tstewart@example.com"
},
{
"userId": 1,
"firstName": "John",
"lastName": "Smith",
"email": "jsmith@example.com"
}
],
...
}
$ curl http://localhost:8080/products
{
"content": [
{
"productId": 101,
"productName": "Pencil",
"description": "Mechanical pencil",
"price": 2.5
},
{
"productId": 1,
"productName": "Notebook",
"description": "200 page notebook",
"price": 7.5
}
],
...
}
$ curl http://localhost:8080/orders
{
"content": [
{
"orderId":"2692e1e9-0bbd-40e8-bf51-4fbcc4e9fea2",
"orderTime":"2022-02-24T02:32:52.60555",
"orderTotal":15.00,
"userId":1,
"users":null,
"products":null
},
{
"orderId":"f7343f22-7dfc-4a18-b4d3-9fcd17161518",
"orderTime":"2022-02-24T02:33:06.832663",
"orderTotal":25.00,
"userId":1,
"users":null,
"products":null
}
]
}