Built on the ASP. 2.0 WebAPI Background Framework (4)-EF core Codefirst database creation

Overview

In the article on the ASP. 2.0 WebAPI Background Framework (2)-EF core (MySQL) Codefirst database migration and Dependency injection, we show you how to quickly build a database in Codefirst quickly, in this chapter, we'll refine the creation of The validation and constraints that can be added in the library.

• Microsoft Dad Official Document: Entity Framework Core

Database operations

(1) Database migration add-migration [any name, must be unique]

(2) Update database update-database

(3) Delete database migration remove-migration

Create a model,divided into data annotations andFluent API, the same effect, see personal habits two choose one

(1) primary key: By convention, the property name is Id or <type name>id will be configured as the key of the entity, or add [key] to specify

[Key]  Public string Get set; }

(2) Self-growth

[Databasegenerated (databasegeneratedoption.identity)]  Public Get set; }

Modelbuilder.entity<blog> (). Property (b=>b.inserted). Valuegeneratedonadd ();

(3) Required or optional properties

The following are allowed null: string, int, byte[], decimal? Wait

The following are not allowed null: int, decimal, bool , etc.

[Required]  Public string Get Set ; }

Modelbuilder.entity<blog> (). Property (b = B.url). IsRequired ();

(4) maximum length, only applicable to array data types, such as string and byte[]

[MaxLength (+)]  Public string Get set; }

modelbuilder.entity<Blog> (). Property (B=>b.url). Hasmaxlength (+);

(5) Custom data table name

[Table ("Dt_blog")]  Public class Blog {}

Modelbuilder.entity<blog> (). ToTable ("dt_blog");

(6) Custom column names

[Column ("Price")]  Public Get set; }

(7) Decimal Precision

[Column ("price", TypeName ="decimal (12,2)")]  Public decimal Get set; }

Modelbuilder.entity<person> (). Property (P=>p.price). Hascolumnname ("price"). Hascolumntype ("decimal (12,2)");;

(8) Batch modification accuracy, add the following code in onmodelcreating

foreach (varintypeof(decimaltypeof(decimal)        ))) {                "decimal (18,4)";        }    

(9) and the starter card

(MySQL)
[Concurrencycheck]  Public Get set; }

(SQL Server) 1537269349  Public byte Get set; }

Modelbuilder.entity<person> (). Property (P=>p.rowversion). Isconcurrencytoken ();

(ten) hide attributes, which are undefined in your. NET entity class but are defined in the EF core model for that entity type

Modelbuilder.entity<blog> (). Property<datetime> ("lastupdated");

(11) The relationship, by convention, is created when the navigation property on the type is found. if the type it points to cannot be mapped to a scalar type by the current database provider, the property is treated as a navigation property.

For a longer length, please refer to the connection:https://docs.microsoft.com/zh-cn/ef/core/modeling/relationships

 Public classBlog { Public intBlogId {Get;Set; } Public stringURL {Get;Set; } PublicList<post> Posts {Get;Set; } } Public classPost { Public intPostID {Get;Set; } Public stringTitle {Get;Set; } Public stringContent {Get;Set; } Public intBlogId {Get;Set; } PublicBlog Blog {Get;Set; } } [ForeignKey ("Blogforeignkey")]  PublicBlog Blog {Get;Set; } [Inverseproperty ("Author")]  PublicList<post> authoredposts {Get;Set; } [Inverseproperty ("Contributor")]  PublicList<post> contributedtoposts {Get;Set; }

Modelbuilder.entity<post> (). HasOne (P=>p.blog). Withmany (b=>b.posts);

(12) Index

Modelbuilder.entity<blog> (). Hasindex (b = b.url). IsUnique (); Modelbuilder.entity<Person> (). Hasindex (p=>new{p.firstname,p.lastname});

(13) Exclude attributes

 Public classBlog { Public intBlogId {Get;Set; } Public stringURL {Get;Set; } PublicBlogmetadata Metadata {Get;Set; }} [Notmapped] Public classBlogmetadata { PublicDateTime Loadedfromdatabase {Get;Set; }}

Modelbuilder.ignore<blogmetadata> ();

(14) Type of exclusion

 Public class Blog {publicintgetset;}  Public string Get Set ; } [Notmapped]  Public Get Set ; }}

Modelbuilder.entity<blog> (). Ignore (b = b.loadedfromdatabase);

Based on the ASP. 2.0 WebAPI Background Framework build (4)-EF core Codefirst database creation