获取sqlserver字段类型和字段最大长度，以及sqlserver数据类型与C#类型对照

获取sqlserver字段类型和字段最大长度

-- nvarchar 等 长度需要除以2
SELECT ColumnType=t.name,Length=c.max_length 
FROM sys.columns c 
left join systypes t on c.system_type_id=t.xtype 
WHERE t.name<>'sysname' 
and OBJECT_NAME(c.object_id)='TableName' 
and c.name='ColumnName'

sqlserver数据类型与C#类型对照

static DbType? GetDbType(string SqlType)
        {
            if (string.IsNullOrWhiteSpace(SqlType)) return null;

            switch (SqlType.ToLower())
            {
                case "bigint":
                    return DbType.Int64;
                case "binary":
                    return DbType.Binary;
                case "bit":
                    return DbType.Boolean;
                case "char":
                    return DbType.AnsiStringFixedLength;
                case "datetime":
                    return DbType.DateTime;
                case "decimal":
                    return DbType.Decimal;
                case "float":
                    return DbType.Double;
                case "image":
                    return DbType.Binary;
                case "int":
                    return DbType.Int32;
                case "money":
                    return DbType.Currency;
                case "nchar":
                    return DbType.StringFixedLength;
                case "ntext":
                    return DbType.String;
                case "nvarchar":
                    return DbType.String;
                case "real":
                    return DbType.Single;
                case "uniqueidentifier":
                    return DbType.Guid;
                case "smalldatetime":
                    return DbType.DateTime;
                case "smallint":
                    return DbType.Int16;
                case "smallmoney":
                    return DbType.Currency;
                case "text":
                    return DbType.AnsiString;
                case "timestamp":
                    return DbType.Binary;
                case "tinyint":
                    return DbType.Byte;
                case "varbinary":
                    return DbType.Binary;
                case "varchar":
                    return DbType.AnsiString;
                case "variant":
                    return DbType.Object;
                case "xml":
                    return DbType.Xml;
                case "udt":
                    return DbType.Object;
                case "structured":
                    return DbType.Object;
                case "date":
                    return DbType.Date;
                case "time":
                    return DbType.Time;
                case "datetime2":
                    return DbType.DateTime2;
                case "datetimeoffset":
                    return DbType.DateTimeOffset;
            }
            return null;
        }