为EntityFrame 实体类 更新数据表结构

最近用EntityFramew 写应用，感觉更新表结构太费事了，于是干脆自己写一个小程序用于将实体类更新到数据库中。

方法如下：

 　　 利用C#的反射，读取EntityFramework实体类的属性

　　　遍历DLL的所有类，找出所有[Table("...")]属性的类，（注:当有设置[NotMapped]不做导入）

　　　　　　再遍历所有[Column("...")] 属性， 

　　　　　　　　Required 对应生成 not null

　　　　　　　　key 对应更新主键

　　生成过程：（生成相应的SQL语句）

　　　　发现不存在的表，则增加 表

　　　　发现不存在的列，则增加 列

　　　　发现主键与实体类不一致，则删除原主键，再插入新主键

  未解决问题：

　　1  数据列名称更改。
　　2  字段类型变更
　　3  预准备的基础数据怎么样导入

  欢迎讨论。

实体类如下：

　　注： Column 属性里必须指定TypeName

    [Table("t_user")]
//    [NotMapped]
    public  class User
    {
        [Key, DatabaseGenerated(DatabaseGeneratedOption.None)]
        [Column("ukey",TypeName="int")]
        public int key { get; set; }
        
        [Column("uName" ,TypeName="varchar(100)")]
        [Required, StringLength(200)]
        public string Name { get; set; }
        
        [Column("uAMT", TypeName = "decimal(18,4)")]
        public float amt { get; set; }

    }

生成代码如下： 为省事直接建了一个console应用程序

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.SqlClient;

namespace GenerateDatabase
{
    class Program
    {
        static bool DEBUG = true;
        static void Main(string[] args)
        {
            string conn = "sql 连接字符串";
            string dll = @"ERP.Businesses.dll"; //DLL及相关需引用的文件最好与EXE放在同一目录下

            Assembly A = Assembly.LoadFrom(dll);
            
            //遍历类
            foreach (Type T in A.GetTypes())
            {
                myTable table = new myTable();
                //遍历属性
                foreach (Object obj in T.GetCustomAttributes(false))
                {
                    //为Table属性
                    if (obj.GetType().Name == "TableAttribute")
                    {
                        TableAttribute tbl = (TableAttribute)obj;
                        table.Name = tbl.Name;
                        table.isTable = true;
                        if (DEBUG) Console.WriteLine(string.Format("发现表{0}", table.Name));
                        foreach (PropertyInfo p in T.GetProperties())
                        {
                            myCol col = new myCol();
                            foreach (Object o in p.GetCustomAttributes(false))
                            {
                                if (o.GetType().Name == "ColumnAttribute")
                                {
                                    ColumnAttribute att = (ColumnAttribute)o;
                                    col.Name = att.Name;
                                    col.Type = att.TypeName;
                                    col.isCol = true;
                                }

                                if (o.GetType().Name == "RequiredAttribute")
                                {
                                    col.isRequire = true;
                                }
                                if ( o.GetType().Name == "KeyAttribute")
                                {
                                    col.isRequire = true;
                                    col.isKey = true;
                                }
                            }

                            if (col.isCol)
                            {
                                table.Columns.Add(col);
                            }
                            if (DEBUG && col.isCol)
                                Console.WriteLine(string.Format("\t列{0} , {1}",col.Name , col.Type ));
                        }

                    }

                    if (obj.GetType().Name == "NotMappedAttribute")
                    {
                        table.noMap = true;
                    }
                }

                //是table时,开始检查表结构
                if (table.isTable && !table.noMap)
                {
                    table.UpdateDatabase(conn);
                }
                
            }

            Console.WriteLine("success!");
            Console.Read();
        }
    }

    public class myCol
    {
        public myCol()
        {
            isRequire = false;
            isKey = false;
            isCol = false;
        }
        public string Name { set; get; }
        public string Type { set; get; }
        public bool isCol { set; get; }
        public bool isRequire { set; get; }
        public bool isKey { set; get; }
        public string NullableString
        {
            get
            {
                return isRequire ? " not null " : "";
            }
        }

    }
    public class myTable
    {
        public myTable()
        {
            Columns = new List<myCol>();
            isTable = false;
        }

        //表名
        public string Name { set; get; }
        public bool noMap { set; get; }
        public bool isTable { set; get; }
        public List<myCol> Columns ;
        private string _conn;
        public void UpdateDatabase(string connectstring)
        {
            if (noMap) return;
            if (!isTable) return;
            _conn = connectstring;

            //this.executeCommand(this.fun_split());
            //如果表不存在,则生成表
            this.executeCommand(this.updateTable());
            //表存在的时候,检查各列,是否存在, 不存在则增加
            foreach (myCol col in Columns)
            {
                this.executeCommand(this.updateCol(col));
            }
            //检查主键是否一致,更新主键
            string sql  = this.updatePaimaryKey();
            this.executeCommand(sql);
        }

        private int executeCommand(string cmdText)
        {
            if (string.IsNullOrEmpty(_conn)) return -999;

            SqlConnection conn = new SqlConnection(_conn);
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandType = System.Data.CommandType.Text;
            cmd.CommandText = cmdText;
            int rlt = cmd.ExecuteNonQuery();
            conn.Close();
            return rlt;

        }

        private string updateTable()
        {
            string sql =string.Format(@"
if object_id('{0}')  is null
create table dbo.{0} (
{1}

    PRIMARY KEY CLUSTERED 
    (
        {2}
    )ON [PRIMARY]
)
", this.Name , this.getCols() , this.getKeyCols());
            return sql ;
        }

        private string updateCol(myCol col)
        {
            string sql = string.Format(@"
if COLUMNPROPERTY( object_id('{0}') , '{1}','ColumnId') is null
alter table {0} add {1} {2} {3}
", this.Name, col.Name , col.Type, col.NullableString );
            return sql;

        }
        private string getCols()
        {
            string sql = "";
            foreach (myCol col in Columns)
            {
                sql += string.Format(",{0} {1} {2} ", col.Name, col.Type, col.NullableString);
            }
            if (sql.Length >= 1)
            {
                sql = sql.Substring(1, sql.Length - 1);
            }
            return sql;
        }
        private string getKeyCols()
        {
            string sql = "";
            foreach (myCol col in Columns)
            {
                if(col.isKey)
                    sql += string.Format(", {0} ", col.Name);
            }
            
            if (sql.Length >= 1)
            {
                sql = sql.Substring(1, sql.Length - 1);
            }
            else
            {
                throw new Exception("表不可以没有主键");
            }
            return sql;
        }

        private string updatePaimaryKey()
        {
            return string.Format(@"
declare @keystring nvarchar(max) , @tablename varchar(1000)
set @keystring = '{1}'
set @tablename = '{0}'

-------------------------拆分字串为表-----------------------------------------------------------------------------
declare @new table(colNew varchar(1000))


    declare @commastr varchar(max),@splitstr varchar(max),@splitlen int,@length int
    declare @splitChar char(1)
    select  @splitChar = ','

    select @splitstr=@keystring,
        @splitlen=charindex(@splitChar,@splitstr),
        @length=datalength(@splitstr)

    while @length>0
    begin
        if     @splitlen=0
                   set @splitlen=@length+1
   
        set    @commastr =@splitstr
        insert @new(colNew) values(substring(@commastr,1,@splitlen-1))
        select @splitstr = substring(@commastr,@splitlen+1,@length),
                   @length=datalength(@splitstr),
                   @splitlen=charindex(@splitChar,@splitstr)
    end
 --------------------------------------------------------------------------------------

declare @Old table(f1 varchar(1000) , f2 varchar(1000) , f3 varchar(1000) ,colOld varchar(500) 
    ,f5 int , PK_Name varchar(1000)
)
insert @Old(f1,f2,f3,colOld,f5,PK_Name)
exec sp_pkeys @tablename


if exists( select *
            from @new  a
            full join @Old b on a.colNew = b.colOld
            where a.colNew is null or b.colOld is null )
begin
declare @pkName varchar(1000)
    select @pkName = PK_Name from @Old
    
    exec('alter table '+@tablename+' drop constraint ' + @pkName) 
    exec('alter table '+@tablename+' add constraint '+ @pkName+' primary key('+@keystring+')')
end


", this.Name ,getKeyCols().Trim()) ;
        }
    }


}