EF Code First creates and initializes a database

1. Preface

Code first is a new programming model provided by the Entity Framework. With code First we can start coding without having established a database, and then build the database from the object. Of course we have to do unit testing in the actual development process. In turn, the library is initialized each time it is tested so that it does not affect the test as a result of the last Test. The following is a concrete implementation.

2. Set up Object 2.1 object

/// <summary>    ///Payment Items/// </summary>     Public classFee_item:feemodel {/// <summary>    ///Payment Items/// </summary>     Public classFee_item:feemodel { PublicFee_item () {type= Feeitemtype.normal;//Enum type initialization} [Required] [Stringlength ( -, Minimumlength =2)]         Public stringName {Get;Set; }//Payment Type[Required] [Stringlength ( -, Minimumlength =2)]         Public stringCode {Get;Set; }  PublicFeeitemtype type {Get;Set; }  Public BOOLState {Get;Set; }//is enabled         Public stringIcon {Get;Set; }//Display icon         Public LongSort {Get;Set; }  Public LongAppID {Get;Set; } } [Required] [Stringlength ( -, Minimumlength =2)]         Public stringName {Get;Set; }//Payment Type[Required] [Stringlength ( -, Minimumlength =2)]         Public stringCode {Get;Set; }  PublicFeeitemtype type {Get;Set; }  Public BOOLState {Get;Set; }//is enabled         Public stringIcon {Get;Set; }//Display icon         Public LongSort {Get;Set; }  Public LongAppID {Get;Set; } }

View Code2.2 Assigning a default value to an object "selectable"

     Public voidInitialize (Feedbcontext context) {List<fee_item> FIM =NewList<fee_item>() {                 NewFee_item () {name="Electricity", code="POW", Type= feeitemtype.normal,state=true, icon="Img/jf_dianf.png", sort=0, appid=0, reg_time=DateTime.Now},NewFee_item () {name="Net fee", code="Net", Type= feeitemtype.normal,state=true, icon="Img/jf_wangf.png", sort=1, appid=1, reg_time=DateTime.Now},NewFee_item () {name="level 46", code="CET", Type= feeitemtype.normal,state=true, icon="Img/jf_siliuj.png", sort=2, appid=2, reg_time=DateTime.Now},NewFee_item () {name="Registration Fee", code="POW", Type= feeitemtype.normal,state=true, icon="Img/jf_baomingf.png", sort=3, appid=3, reg_time=DateTime.Now},NewFee_item () {name="Insurance Premiums", code="POW", Type= feeitemtype.normal,state=false, icon="Img/jf_baox.png", sort=4, appid=4, reg_time=DateTime.Now},NewFee_item () {name="Accommodation fee", code="POW", Type= feeitemtype.normal,state=true, icon="Img/jf_dianf.png", sort=5, appid=5, reg_time=DateTime.Now}}; List<school_power> Con_power =NewList<school_power>() {             NewSchool_power () {oid=1, power_code="Ykt", power_id="1", reg_time=DateTime.Now},NewSchool_power () {oid=1, power_code="Sims", power_id="2", reg_time=DateTime.Now}}; Fim. ForEach (o=Context.fee_item.           ADD (o)); Context.        SaveChanges (); }

View Code3.DBContext

   Public classFeedbcontext:dbcontext { PublicFeedbcontext ():Base("Feedbcontext") { }         PublicDbset<fee_item> Fee_item {Get;Set; } protected Override voidonmodelcreating (Dbmodelbuilder modelBuilder) {Base.            Onmodelcreating (ModelBuilder); ModelBuilder.Conventions.Remove<PluralizingTableNameConvention>(); }    }

View Code4.EF Code First4.1 New

 Public BOOLBuild () {Try            {                varContext =NewFeedbcontext (); if(!context. Database.exists ()) {NewList<idatainitializer<feedbcontext>>() {                         Newdatainit4dept ()}. Setup<FeeDbContext>(context); return true; }                return false; }            Catch(Dbentityvalidationexception ex) {StringBuilder error=NewStringBuilder (); foreach(varIteminchEx. entityvalidationerrors) {foreach(varItem2inchitem. validationerrors) {error. Append (string. Format ("{0}:{1}\r\n", item2. PropertyName, Item2.                    errormessage)); }} Console.WriteLine ("Database initialization error:"+error); Throwex; }            Catch(Exception e) {Console.WriteLine ("Database initialization error:"+e.message); Throwe; }        }

View Code4.2 Removal

  Public BOOLRemove () {varContext =NewFeedbcontext (); Try            {                if(context. Database.exists ()) {returncontext.                Database.delete (); }                return true; }            Catch(Exception e) {Console.WriteLine ("Database initialization error:"+e.message); return false; }            finally{context. Dispose (); }        }

View Code4.3 initialization

 Public BOOL Rebuild ()        {            return Remove () && Build ();        }

View Code

EF Code First creates and initializes a database