(精华)2020年8月11日 C#基础知识点 数据库自动生成实体类

(精华)2020年8月11日 C#基础知识点 数据库自动生成实体类

数据库相关的sql

//获取所有的数据库名
private static string GetAllDataSql = "SELECT NAME FROM MASTER.DBO.SYSDATABASES ORDER BY NAME";
//获取所有的表名
private static string GetAllTableSql = "SELECT name FROM sys.tables where type ='U'";
//获取所有的表信息
private static string GetTableInfoSql = @"SELECT DISTINCT a.COLUMN_NAME columnName, 
                                          a.DATA_TYPE typeName, a.IS_NULLABLE isnullAble
                                          From INFORMATION_SCHEMA.Columns a LEFT JOIN 
                                          INFORMATION_SCHEMA.KEY_COLUMN_USAGE b ON a.TABLE_NAME=b.TABLE_NAME ";

模型相关方法

//根据表名创建模型
public static void CreateSingleModel(string tableName)
        {<!-- -->
            string sql = $"{GetTableInfoSql}  where a.table_name='{tableName}'";
            using (SqlConnection conn = new SqlConnection(ConnectionString))//ConnectionString为自己连接字符串
            {<!-- -->
                SqlCommand sqlCommand = new SqlCommand(sql, conn);
                conn.Open();
                SqlDataReader reader = sqlCommand.ExecuteReader();
                StringBuilder stringBuilder = new StringBuilder();
                stringBuilder.Append($"public class {tableName} \r\n{<!-- -->{\r\n");
                while (reader.Read())
                {<!-- -->
                    stringBuilder.Append($"  public {GetTypeOfColumn(reader["typeName"].ToString(), reader["isnullAble"].ToString())} {reader["columnName"]} {<!-- -->{get;set;}}\r\n");
                }
                stringBuilder.Append("} \r\n");
                string directory = string.IsNullOrEmpty(StaticConfiguration.FieldPath) ? AppDomain.CurrentDomain.BaseDirectory + "\\Model\\": FieldPath;//FieldPath为自己文件路径
                StreamWriter sr;
                //是否存在文件夹,不存在则创建
                if (!Directory.Exists(directory))
                {<!-- -->
                    Directory.CreateDirectory(directory);
                }
                string path = directory + "\\" + tableName + ".txt";
                //如果该文件存在则追加内容，否则创建文件
                if (File.Exists(path))
                {<!-- -->
                    sr = File.AppendText(path);
                }
                else
                {<!-- -->
                    sr = File.CreateText(path);
                }
                sr.Write(stringBuilder.ToString());
                sr.Flush();
                sr.Close();
            }
        }

//根据数据库直接生成所有模型
public static void BatchCreateModel()
        {<!-- -->
            using (SqlConnection conn = new SqlConnection(ConnectionString))//ConnectionString为自己连接字符串
            {<!-- -->
                SqlCommand sqlCommand = new SqlCommand(GetAllTableSql, conn);
                conn.Open();
                SqlDataReader reader = sqlCommand.ExecuteReader();
                while (reader.Read())
                {<!-- -->
                    CreateSingleModel(reader["name"].ToString());
                }
            }
        }

其他辅助类

//获取列的类型
private static string GetTypeOfColumn(string type, string nullAble)
        {<!-- -->
            if (type.Equals("int") && nullAble.Equals("NO"))
                return "int";
            else if (type.Equals("int") && nullAble.Equals("YES"))
                return "int?";
            else if (type.Equals("bit") && nullAble.Equals("Not"))
                return "bool";
            else if (type.Equals("bit") && nullAble.Equals("YES"))
                return "bool?";
            else if ((type.Equals("decimal")|| type.Equals("numeric")|| type.Equals("float") || type.Equals("real"))  && nullAble.Equals("NO")) 
                return "decimal";
            else if ((type.Equals("decimal") || type.Equals("numeric") || type.Equals("float") || type.Equals("real")) && nullAble.Equals("Yes"))
                return "decimal?";
            else if (type.Equals("datetime") && nullAble.Equals("YES"))
                return "DateTime?";
            else if (type.Equals("datetime") && nullAble.Equals("NO"))
                return "DateTime";
            else if (type.Equals("nchar") || type.Equals("char") || type.Equals("nvarchar") || type.Equals("varchar") || type.Equals("text"))
                return "string";
            else throw new Exception("无此类型");
        }