如何从SQL Server表对象生成类?
我说的不是使用ORM。我只需要创建实体(简单类)。喜欢的东西:
public class Person
{
public string Name { get;set; }
public string Phone { get;set; }
}
给定一个表，比如:
+----+-------+----------------+
| ID | Name | Phone |
+----+-------+----------------+
| 1 | Alice | (555) 555-5550 |
| 2 | Bob | (555) 555-5551 |
| 3 | Cathy | (555) 555-5552 |
+----+-------+----------------+
当前回答
我很困惑你想要从这里得到什么，但这里是在设计你想要设计的东西时的一般选择。
在Visual Studio版本中使用内置的ORM。 自己编写一个，类似于您的代码示例。通常情况下，如果你不确定怎么做，教程是你最好的朋友。 使用另一种ORM，如NHibernate。
其他回答
设置@TableName为你的表名。
declare @TableName sysname = 'TableName'
declare @Result varchar(max) = 'public class ' + @TableName + '
{'
select @Result = @Result + '
public ' + ColumnType + NullableSign + ' ' + ColumnName + ' { get; set; }
'
from
(
select
replace(col.name, ' ', '_') ColumnName,
column_id ColumnId,
case typ.name
when 'bigint' then 'long'
when 'binary' then 'byte[]'
when 'bit' then 'bool'
when 'char' then 'string'
when 'date' then 'DateTime'
when 'datetime' then 'DateTime'
when 'datetime2' then 'DateTime'
when 'datetimeoffset' then 'DateTimeOffset'
when 'decimal' then 'decimal'
when 'float' then 'double'
when 'image' then 'byte[]'
when 'int' then 'int'
when 'money' then 'decimal'
when 'nchar' then 'string'
when 'ntext' then 'string'
when 'numeric' then 'decimal'
when 'nvarchar' then 'string'
when 'real' then 'float'
when 'smalldatetime' then 'DateTime'
when 'smallint' then 'short'
when 'smallmoney' then 'decimal'
when 'text' then 'string'
when 'time' then 'TimeSpan'
when 'timestamp' then 'long'
when 'tinyint' then 'byte'
when 'uniqueidentifier' then 'Guid'
when 'varbinary' then 'byte[]'
when 'varchar' then 'string'
else 'UNKNOWN_' + typ.name
end ColumnType,
case
when col.is_nullable = 1 and typ.name in ('bigint', 'bit', 'date', 'datetime', 'datetime2', 'datetimeoffset', 'decimal', 'float', 'int', 'money', 'numeric', 'real', 'smalldatetime', 'smallint', 'smallmoney', 'time', 'tinyint', 'uniqueidentifier')
then '?'
else ''
end NullableSign
from sys.columns col
join sys.types typ on
col.system_type_id = typ.system_type_id AND col.user_type_id = typ.user_type_id
where object_id = object_id(@TableName)
) t
order by ColumnId
set @Result = @Result + '
}'
print @Result
你刚刚做了，只要你的表包含两列，并被称为'tblPeople'之类的东西。
您总是可以编写自己的SQL包装器。实际上我更喜欢这样做，我讨厌生成代码，以任何方式。
也许创建一个DAL类，并有一个名为GetPerson(int id)的方法，用于查询数据库中的person，然后从结果集中创建person对象。
我只是想表达我的意见
0) QueryFirst https://marketplace.visualstudio.com/items?itemName=bbsimonbb.QueryFirst Query-first is a visual studio extension for working intelligently with SQL in C# projects. Use the provided .sql template to develop your queries. When you save the file, Query-first runs your query, retrieves the schema and generates two classes and an interface: a wrapper class with methods Execute(), ExecuteScalar(), ExecuteNonQuery() etc, its corresponding interface, and a POCO encapsulating a line of results.
1) Sql2Objects 从查询结果开始创建类(但不是DAL)
2) https://learn.microsoft.com/en-us/ef/ef6/resources/tools
3) https://visualstudiomagazine.com/articles/2012/12/11/sqlqueryresults-code-generation.aspx
4) http://www.codesmithtools.com/product/generator#features
我无法让亚历克斯的答案在Sql Server 2008 R2上工作。所以，我用同样的基本原理重写了它。它现在支持模式，并且对列属性映射(包括将可为空的日期类型映射为可为空的c#值类型)进行了一些修复。下面是Sql语句:
DECLARE @TableName VARCHAR(MAX) = 'NewsItem' -- Replace 'NewsItem' with your table name
DECLARE @TableSchema VARCHAR(MAX) = 'Markets' -- Replace 'Markets' with your schema name
DECLARE @result varchar(max) = ''
SET @result = @result + 'using System;' + CHAR(13) + CHAR(13)
IF (@TableSchema IS NOT NULL)
BEGIN
SET @result = @result + 'namespace ' + @TableSchema + CHAR(13) + '{' + CHAR(13)
END
SET @result = @result + 'public class ' + @TableName + CHAR(13) + '{' + CHAR(13)
SET @result = @result + '#region Instance Properties' + CHAR(13)
SELECT
@result = @result + CHAR(13)
+ ' public ' + ColumnType + ' ' + ColumnName + ' { get; set; } ' + CHAR(13)
FROM (SELECT
c.COLUMN_NAME AS ColumnName,
CASE c.DATA_TYPE
WHEN 'bigint' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'Int64?'
ELSE 'Int64'
END
WHEN 'binary' THEN 'Byte[]'
WHEN 'bit' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'bool?'
ELSE 'bool'
END
WHEN 'char' THEN 'string'
WHEN 'date' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'DateTime?'
ELSE 'DateTime'
END
WHEN 'datetime' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'DateTime?'
ELSE 'DateTime'
END
WHEN 'datetime2' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'DateTime?'
ELSE 'DateTime'
END
WHEN 'datetimeoffset' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'DateTimeOffset?'
ELSE 'DateTimeOffset'
END
WHEN 'decimal' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'decimal?'
ELSE 'decimal'
END
WHEN 'float' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'Single?'
ELSE 'Single'
END
WHEN 'image' THEN 'Byte[]'
WHEN 'int' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'int?'
ELSE 'int'
END
WHEN 'money' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'decimal?'
ELSE 'decimal'
END
WHEN 'nchar' THEN 'string'
WHEN 'ntext' THEN 'string'
WHEN 'numeric' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'decimal?'
ELSE 'decimal'
END
WHEN 'nvarchar' THEN 'string'
WHEN 'real' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'Double?'
ELSE 'Double'
END
WHEN 'smalldatetime' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'DateTime?'
ELSE 'DateTime'
END
WHEN 'smallint' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'Int16?'
ELSE 'Int16'
END
WHEN 'smallmoney' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'decimal?'
ELSE 'decimal'
END
WHEN 'text' THEN 'string'
WHEN 'time' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'TimeSpan?'
ELSE 'TimeSpan'
END
WHEN 'timestamp' THEN 'Byte[]'
WHEN 'tinyint' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'Byte?'
ELSE 'Byte'
END
WHEN 'uniqueidentifier' THEN CASE C.IS_NULLABLE
WHEN 'YES' THEN 'Guid?'
ELSE 'Guid'
END
WHEN 'varbinary' THEN 'Byte[]'
WHEN 'varchar' THEN 'string'
ELSE 'Object'
END AS ColumnType,
c.ORDINAL_POSITION
FROM INFORMATION_SCHEMA.COLUMNS c
WHERE c.TABLE_NAME = @TableName
AND ISNULL(@TableSchema, c.TABLE_SCHEMA) = c.TABLE_SCHEMA) t
ORDER BY t.ORDINAL_POSITION
SET @result = @result + CHAR(13) + '#endregion Instance Properties' + CHAR(13)
SET @result = @result + '}' + CHAR(13)
IF (@TableSchema IS NOT NULL)
BEGIN
SET @result = @result + CHAR(13) + '}'
END
PRINT @result
它生成的c#代码如下所示:
using System;
namespace Markets
{
public class NewsItem {
#region Instance Properties
public Int32 NewsItemID { get; set; }
public Int32? TextID { get; set; }
public String Description { get; set; }
#endregion Instance Properties
}
}
It may be an idea to use EF, Linq to Sql, or even Scaffolding; however, there are times when a piece of coding like this comes in handy. Frankly, I do not like using EF navigation properties where the code it generates made 19,200 separate database calls to populate a 1000 row grid. This could have been achieved in a single database call. Nonetheless, it could just be that your technical architect does not want you to use EF and the like. So, you have to revert to code like this... Incidentally, it may also be an idea to decorate each of the properties with attributes for DataAnnotations, etc., but I'm keeping this strictly POCO.
编辑 修正了时间戳和Guid?
是的，这些是伟大的，如果你使用一个简单的ORM像Dapper。
如果你使用。net，你可以在运行时使用WriteXmlSchema方法用任何数据集生成XSD文件。http://msdn.microsoft.com/en-us/library/xt7k72x8 (v = vs.110) . aspx
是这样的:
using (SqlConnection cnn = new SqlConnection(mConnStr)) {
DataSet Data = new DataSet();
cnn.Open();
string sql = "SELECT * FROM Person";
using (SqlDataAdapter Da = new SqlDataAdapter(sql, cnn))
{
try
{
Da.Fill(Data);
Da.TableMappings.Add("Table", "Person");
Data.WriteXmlSchema(@"C:\Person.xsd");
}
catch (Exception ex)
{ MessageBox.Show(ex.Message); }
}
cnn.Close();
从那里，您可以使用xsd.exe创建一个可从开发人员命令提示符序列化XML的类。 http://msdn.microsoft.com/en-us/library/x6c1kb0s (v = vs.110) . aspx
是这样的:
xsd C:\Person.xsd /classes /language:CS
