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
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
其他回答
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?
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。
Visual Studio杂志发表了这篇文章:
为SQL查询结果生成。net POCO类
它有一个可下载的项目，你可以构建，给它你的SQL信息，它会为你制作出类。
现在，如果该工具刚刚为SELECT、INSERT和UPDATE创建了SQL命令....
我只是想给感兴趣的人加上我自己的答案。 主要特点有:
It will automatically generate classes for all the tables in the entire schema. Just specify the schema name. It will add System.Data.Linq.Mapping attributes to the class and each property. Useful for anyone using Linq to SQL. declare @TableName sysname declare @Result varchar(max) declare @schema varchar(20) = 'dbo' DECLARE @Cursor CURSOR SET @Cursor = CURSOR FAST_FORWARD FOR SELECT DISTINCT tablename = rc1.TABLE_NAME FROM INFORMATION_SCHEMA.Tables rc1 where rc1.TABLE_SCHEMA = @schema OPEN @Cursor FETCH NEXT FROM @Cursor INTO @TableName WHILE (@@FETCH_STATUS = 0) BEGIN set @Result = '[Table(Name = "' + @schema + '.' + @TableName + '")] public class ' + Replace(@TableName, '$', '_') + ' {' select @Result = @Result + ' [Column' + PriKey +'] public ' + ColumnType + NullableSign + ' ' + ColumnName + ' { get; set; } ' from ( select replace(col.name, ' ', '_') ColumnName, col.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, case when pk.CONSTRAINT_NAME is not null and ic.column_id is not null then '(IsPrimaryKey = true, IsDbGenerated = true)' when pk.CONSTRAINT_NAME is not null then '(IsPrimaryKey = true)' when ic.column_id is not null then '(IsDbGenerated = true)' else '' end PriKey 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 left outer join sys.identity_columns ic on ic.column_id = col.column_id and col.object_id = ic.object_id left outer join ( SELECT K.TABLE_NAME , K.COLUMN_NAME , K.CONSTRAINT_NAME FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS C JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS K ON C.TABLE_NAME = K.TABLE_NAME AND C.CONSTRAINT_CATALOG = K.CONSTRAINT_CATALOG AND C.CONSTRAINT_SCHEMA = K.CONSTRAINT_SCHEMA AND C.CONSTRAINT_NAME = K.CONSTRAINT_NAME where C.CONSTRAINT_TYPE = 'PRIMARY KEY' ) pk on pk.COLUMN_NAME = col.name and pk.TABLE_NAME = @TableName where col.object_id = object_id(@schema + '.' + @TableName) ) t order by ColumnId set @Result = @Result + ' } ' print @Result FETCH NEXT FROM @Cursor INTO @TableName end CLOSE @Cursor DEALLOCATE @Cursor GO
增加了6-29-22:这是为EF Core (dotNet 6.0)生成模型的更新版本。
CREATE FUNCTION [dbo].[InitCap] ( @InputString varchar(4000) )
RETURNS VARCHAR(4000)
AS
BEGIN
DECLARE @Index INT
DECLARE @Char CHAR(1)
DECLARE @PrevChar CHAR(1)
DECLARE @OutputString VARCHAR(4000)
SET @OutputString = @InputString
SET @Index = 1
WHILE @Index <= LEN(@InputString)
BEGIN
SET @Char = SUBSTRING(@InputString, @Index, 1)
SET @PrevChar = CASE WHEN @Index = 1 THEN ' '
ELSE SUBSTRING(@InputString, @Index - 1, 1)
END
IF @PrevChar IN (' ', ';', ':', '!', '?', ',', '.', '_', '-', '/', '&', '''', '(')
SET @OutputString = STUFF(@OutputString, @Index, 1, UPPER(@Char))
SET @Index = @Index + 1
END
RETURN @OutputString
END
go
declare @TableName sysname
declare @Result varchar(max)
declare @schema varchar(20) = 'dbo'
DECLARE @Cursor CURSOR
SET @Cursor = CURSOR FAST_FORWARD FOR
SELECT DISTINCT tablename = rc1.TABLE_NAME
FROM INFORMATION_SCHEMA.Tables rc1
where rc1.TABLE_SCHEMA = @schema
OPEN @Cursor FETCH NEXT FROM @Cursor INTO @TableName
WHILE (@@FETCH_STATUS = 0)
BEGIN
set @Result = '[Table("' + @TableName + '", Schema = "' + @schema + '")]
public class ' + Replace(@TableName, '$', '_') + '
{'
select @Result = @Result + '
[Column("' + ColumnName + '"' + stringType + ')]
public ' + ColumnType + NullableSign + ' ' + PropertyName + ' { get; set; }
'
from
(
select
replace(col.name, ' ', '_') ColumnName,
replace(replace([dbo].[InitCap](col.name), ' ', ''), '_', '') PropertyName,
col.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
then '?'
else ''
end NullableSign,
case
when typ.name in ('char', 'nchar', 'nvarchar', 'varchar')
then ', TypeName = "' + typ.name + '(' + convert(varchar, col.max_length) + ')"'
else ''
end stringType
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
left outer join sys.identity_columns ic on ic.column_id = col.column_id and col.object_id = ic.object_id
left outer join (
SELECT K.TABLE_NAME ,
K.COLUMN_NAME ,
K.CONSTRAINT_NAME
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS C
JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS K ON C.TABLE_NAME = K.TABLE_NAME
AND C.CONSTRAINT_CATALOG = K.CONSTRAINT_CATALOG
AND C.CONSTRAINT_SCHEMA = K.CONSTRAINT_SCHEMA
AND C.CONSTRAINT_NAME = K.CONSTRAINT_NAME
where C.CONSTRAINT_TYPE = 'PRIMARY KEY'
) pk on pk.COLUMN_NAME = col.name and pk.TABLE_NAME = @TableName
where col.object_id = object_id(@schema + '.' + @TableName)
) t
order by ColumnId
set @Result = @Result + '
}
'
print @Result
FETCH NEXT FROM @Cursor INTO @TableName
end
CLOSE @Cursor DEALLOCATE @Cursor
GO
DROP FUNCTION [dbo].[InitCap]
GO
要打印NULLABLE属性，请使用此命令。 它对Alex Aza的CASE语句块脚本进行了轻微修改。
declare @TableName sysname = 'TableName'
declare @result varchar(max) = 'public class ' + @TableName + '
{'
select @result = @result + '
public ' + ColumnType + ' ' + ColumnName + ' { get; set; }
'
from
(
select
replace(col.name, ' ', '_') ColumnName,
column_id,
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 'float'
when 'image' then 'byte[]'
when 'int' then 'int'
when 'money' then 'decimal'
when 'nchar' then 'char'
when 'ntext' then 'string'
when 'numeric' then 'decimal'
when 'nvarchar' then 'string'
when 'real' then 'double'
when 'smalldatetime' then 'DateTime'
when 'smallint' then 'short'
when 'smallmoney' then 'decimal'
when 'text' then 'string'
when 'time' then 'TimeSpan'
when 'timestamp' then 'DateTime'
when 'tinyint' then 'byte'
when 'uniqueidentifier' then 'Guid'
when 'varbinary' then 'byte[]'
when 'varchar' then 'string'
else 'UNKNOWN_' + typ.name
end +
CASE
WHEN col.is_nullable=1 AND
typ.name NOT IN (
'binary', 'varbinary', 'image',
'text', 'ntext',
'varchar', 'nvarchar', 'char', 'nchar')
THEN '?'
ELSE '' END AS [ColumnType]
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 column_id
set @result = @result + '
}'
print @result
