C# 与 SQL Server 的数据类型对应关系

(一)C#与SQL Server 2005（或以下版本）：

C#	C#取值	SQL Server	SQL Server取值
System.DateTime		samlltime
System.Object		variant

(二)C#与SQL Server 2008（或以上版本）：

C#	C#取值	SQL Server	SQL Server取值
System.Boolean	true/false	bit	1/0
System.SByte	-128~127
System.Byte	0~255	tinyint	0~255
System.Int16	-32768~32767	smallint	-32768~32767
System.UInt16	0~65535
System.Int32	-2147483648~2147483647	int	-2147483648~2147483647
System.UInt32	0~4294967295
System.Int64	-9223372036854775808~ 9223372036854775807L	bigint	-9223372036854775808~9223372036854775807
System.UInt64	0~18446744073709551615UL
System.Single		real
System.Double		float
System.Decimal		smallmoney	-214748.3648~214748.3647
		money	-922337203685477.5808~922337203685477.5807
		decimal	-999999999999999999.49~999999999999999999.49
		numeric	1~38位
System.Char
System.String		char	1~8000
		varchar	1~8000
		nchar	1~4000
		nvarchar	1~4000
		text
		ntext
		time	00:00:00.0000000~23:59:59.9999999
System.DateTime		date	0001-01-01~9999-12-31
		smalldatetime
		datetime	1753-01-01 00:00:00:000~9999-12-31 23:59:59.997
		datetime2
		datetimeoffset
System.Byte[]		timestamp
		image
		binary
		varbinary
System.Guid		uniqueidentifier
System.Object		sql_variant

(三)根据数据库数据类型字符，获取C#中对应的数据类型字符

 1 /// <summary>
 2 /// 将数据库数据类型字符串，转为C#数据类型字符串。
 3 /// </summary>
 4 /// <param name="dbType">数据库数据类型字符串。</param>
 5 /// <returns>C#数据类型字符串。</returns>
 6 private static string DBTypeToCSharpType(string dbType)
 7 {
 8     string cSharpType = string.Empty;
 9     switch (dbType.ToLower())
10     {
11         case "bit":
12             cSharpType = "bool";
13             break;
14         case "tinyint":
15             cSharpType = "byte";
16             break;
17         case "smallint":
18             cSharpType = "short";
19             break;
20         case "int":
21             cSharpType = "int";
22             break;
23         case "bigint":
24             cSharpType = "long";
25             break;
26         case "real":
27             cSharpType = "float";
28             break;
29         case "float":
30             cSharpType = "double";
31             break;
32         case "smallmoney":
33         case "money":
34         case "decimal":
35         case "numeric":
36             cSharpType = "decimal";
37             break;
38         case "char":
39         case "varchar":
40         case "nchar":
41         case "nvarchar":
42         case "text":
43         case "ntext":
44             cSharpType = "string";
45             break;
46         case "samlltime":
47         case "date":
48         case "smalldatetime":
49         case "datetime":
50         case "datetime2":
51         case "datetimeoffset":
52             cSharpType = "System.DateTime";
53             break;
54         case "timestamp":
55         case "image":
56         case "binary":
57         case "varbinary":
58             cSharpType = "byte[]";
59             break;
60         case "uniqueidentifier":
61             cSharpType = "System.Guid";
62             break;
63         case "variant":
64         case "sql_variant":
65             cSharpType = "object";
66             break;
67         default:
68             cSharpType = "string";
69             break;
70     }
71     return cSharpType;
72 }