Entityframewrok Codefirst Database Initialization

We want to automatically complete the creation of the database and preset the initial values when the program runs. Their context is named Databasecontet.

There are two ways of doing this:

1, add database.setinitializer<databasecontext> (New Databaseinitializer ()) in Global.asax;

2. Add the Contexts node to the configuration file, specifying the class name and namespace in the node

<entityFramework> <contexts> <context type="Database.databasecontext, DataBase"disabledatabaseinitialization="False"> <databaseinitializer type="Database.databaseinitializer, DataBase"/> </context> </contexts> <defaultconnectionfactory type="Database.databasecontext, DataBase"> <parameters> <parameter value="v11.0"/> </parameters> </defaultConnectionFactory> <providers> <provider invariantname="System.Data.SqlClient"Type="System.Data.Entity.SqlServer.SqlProviderServices, Entityframework.sqlserver"/> </providers> </entityFramework>

Where Databasecontext is:

namespacedatabase{ Public classDatabasecontext:dbcontext { PublicDatabasecontext ():Base("default")        {                       //whether to enable lazy loading://true: Lazy Loading: Gets the entity when its navigation property is not loaded and is automatically loaded once the navigation property is used//false: Direct load (Eager loading): Displays the load navigation properties via methods such as include, gets the entity immediately loads the navigation properties specified by the Include             This. configuration.lazyloadingenabled =true;  This. configuration.autodetectchangesenabled =true;//automatic monitoring of changes, the default value is True        }               protected Override voidonmodelcreating (Dbmodelbuilder modelBuilder) {Base.        Onmodelcreating (ModelBuilder); }         PublicDbset<usermodels> UserContext {Get;Set; }  PublicDbset<pigmodels> Pigcontext {Get;Set; } }}

Custom data initialization method: Databaseinitializer, which inherits dropcreatedatabasealways only for demonstration purposes, is selected as needed in the actual project.

namespacedatabase{ Public classDatabaseinitializer:dropcreatedatabasealways<databasecontext>    {        protected Override voidSeed (Databasecontext context) {Usermodels M1=NewUsermodels () {Userguid=Guid.NewGuid (). ToString (), UserName="Zhang Yi", Usernumber="0001", Userbirthday="1990.1.1", Usermail="[email protected]", Userphone="13100001111", Password="aaaaaa"            }; Usermodels m2=NewUsermodels () {Userguid=Guid.NewGuid (). ToString (), UserName="Zhang Yi", Usernumber="0002", Userbirthday="1989.12.12", Usermail="[email protected]", Userphone="13100002222", Password="aaaaaa"            }; Usermodels M3=NewUsermodels () {Userguid=Guid.NewGuid (). ToString (), UserName="Zhang San", Usernumber="0003", Userbirthday="1989.12.12", Usermail="[email protected]", Userphone="13100003333", Password="aaaaaa"            }; Try{//Write Databasecontext.            Usercontext.add (M1); Context.            Usercontext.add (m2); Context.            Usercontext.add (m3); Context.            SaveChanges (); }            Catch(Dbentityvalidationexception dbex) {}Base.        Seed (context); }    }}

Specific steps:

First installs the EntityFramework through the NuGet tool, I use 6.0 version.

1, establish the entity class:

namespace databasemodels{public    class Usermodels    {        [Required]        [Key] public        string Userguid {get ; Set }        [Required]        [Display (name = "user name")] public        string  UserName {get; set;}        [Display (Name = "User work number")]        public string Usernumber {get; set;}        [Required]        [DataType (Datatype.password)]        [Display (Name = "password")]        public string Password {get; set;}        [Display (Name = "date of birth")]        public string Userbirthday {get; set;}        [Display (Name = "phone number")]        public string Userphone {get; set;}        [Display (Name = "Mailbox")]        public string Usermail {get; set;}}           }

2. Establishing the context inheritance DbContext

namespace database{public    class Databasecontext:dbcontext    {public        databasecontext ()            : Base (" Default ")        {//                       whether lazy loading is enabled:              //  true: Lazy   loading (lazy Loading): When an entity is fetched, its navigation property is not loaded and is automatically loaded once the navigation property is used  false:  Direct loading (Eager loading): Displays the load navigation properties via methods such as include, gets the entity immediately loads the navigation properties specified by the Include this              . Configuration.lazyloadingenabled = true;            This. Configuration.autodetectchangesenabled = true;  Automatic monitoring of changes, default value True          }               protected override void Onmodelcreating (Dbmodelbuilder modelBuilder)        {            Base. Onmodelcreating (ModelBuilder);        }        Public dbset<usermodels> UserContext {get; set;}}            }

3. Create data initial method

namespacedatabase{ Public classDatabaseinitializer:dropcreatedatabasealways<databasecontext>    {        protected Override voidSeed (Databasecontext context) {Usermodels M1=NewUsermodels () {Userguid=Guid.NewGuid (). ToString (), UserName="Zhang Yi", Usernumber="0001", Userbirthday="1990.1.1", Usermail="[email protected]", Userphone="13100001111", Password="aaaaaa"            }; Usermodels m2=NewUsermodels () {Userguid=Guid.NewGuid (). ToString (), UserName="Zhang Yi", Usernumber="0002", Userbirthday="1989.12.12", Usermail="[email protected]", Userphone="13100002222", Password="aaaaaa"            }; Usermodels M3=NewUsermodels () {Userguid=Guid.NewGuid (). ToString (), UserName="Zhang San", Usernumber="0003", Userbirthday="1989.12.12", Usermail="[email protected]", Userphone="13100003333", Password="aaaaaa"            }; Try{//Write Databasecontext.            Usercontext.add (M1); Context.            Usercontext.add (m2); Context.            Usercontext.add (m3); Context.            SaveChanges (); }            Catch(Dbentityvalidationexception dbex) {}Base.        Seed (context); }    }}

4.

Method One, add database.setinitializer<databasecontext> (New Databaseinitializer ()) in Global.asax;

Or: Method Two: Add a node to the configuration file:

<Contexts>      <Contexttype= "Database.databasecontext, DataBase"disabledatabaseinitialization= "false">        <Databaseinitializertype= "Database.databaseinitializer, DataBase" />      </Context>    </Contexts>

Entityframewrok Codefirst Database Initialization