Sqlite installation and use

Sqlite features

Sqlite is a lightweight database that does not require installation and can be used across platforms. It is the optimal solution for small software, small projects, and rapid transplantation. There is no need to install the database first like mysql and Sqlserver, and then use it.

Environment installation

Net.Core =6.0

project files

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EF.Sqlite: Sqlite lightweight database, no need to install, only need to import Nuget package

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EF.Tool: Database transfer tool, .Net defaults to Sqlserver. This is to transfer database management objects from Sqlserver to sqlite

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EF framework introduction

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What are EFs?

EF is an ORM entity-relationship database, what is ORM? Simply put, ORM means that the objects that our program runs are consistent with the objects stored in the database. The database is just one place where the data we run is persisted. A database is simply a large, persistent array of objects.

example

EF uses

Create two new files

DbContext.cs: database corresponding class, used for sql operation
DtName.cs: The corresponding class of the data table, used to design the corresponding fields of the data table, Id does not need

example

Database: MyToDoDbContext, inherited from DbContext

using Microsoft.EntityFrameworkCore;

namespace MyToDo.Api.Context
{
    
    
    public class MyToDoContext:DbContext
    {
    
    
        public MyToDoContext(DbContextOptions<MyToDoContext> options):base(options)
        {
    
    //继承DbContext建库方法
            
        }
        public DbSet<ToDo> ToDo {
    
     get; set; }


    }
}

Data table corresponding entity: ToDo class

namespace MyToDo.Api.Context
{
    
    
    public class ToDo 
    {
    
    
        public string Title {
    
     get; set; }

        public string Content {
    
     get; set; }

        public int Status {
    
     get; set; }
    }
}

Add database connection string in json

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{
    
    
  "ConnectionStrings": {
    
    
    "ToDoConnection": "Data Source=to.do"
  },
  ...
}

Set in Program, refer to sqlite

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builder.Services.AddDbContext<MyToDoContext>(options =>
{
    
    
//这个是我们在appsettings.json里面添加的数据库连接串
    var connectionStr = builder.Configuration.GetConnectionString("ToDoConnection");

    options.UseSqlite(connectionStr);
});