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
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。
其他回答
为了感谢Alex的解决方案和Guilherme的要求，我为MySQL生成c#类做了这个
set @schema := 'schema_name';
set @table := 'table_name';
SET group_concat_max_len = 2048;
SELECT
concat('public class ', @table, '\n{\n', GROUP_CONCAT(a.property_ SEPARATOR '\n'), '\n}') class_
FROM
(select
CONCAT(
'\tpublic ',
case
when DATA_TYPE = 'bigint' then 'long'
when DATA_TYPE = 'BINARY' then 'byte[]'
when DATA_TYPE = 'bit' then 'bool'
when DATA_TYPE = 'char' then 'string'
when DATA_TYPE = 'date' then 'DateTime'
when DATA_TYPE = 'datetime' then 'DateTime'
when DATA_TYPE = 'datetime2' then 'DateTime'
when DATA_TYPE = 'datetimeoffset' then 'DateTimeOffset'
when DATA_TYPE = 'decimal' then 'decimal'
when DATA_TYPE = 'double' then 'double'
when DATA_TYPE = 'float' then 'float'
when DATA_TYPE = 'image' then 'byte[]'
when DATA_TYPE = 'int' then 'int'
when DATA_TYPE = 'money' then 'decimal'
when DATA_TYPE = 'nchar' then 'char'
when DATA_TYPE = 'ntext' then 'string'
when DATA_TYPE = 'numeric' then 'decimal'
when DATA_TYPE = 'nvarchar' then 'string'
when DATA_TYPE = 'real' then 'double'
when DATA_TYPE = 'smalldatetime' then 'DateTime'
when DATA_TYPE = 'smallint' then 'short'
when DATA_TYPE = 'smallmoney' then 'decimal'
when DATA_TYPE = 'text' then 'string'
when DATA_TYPE = 'time' then 'TimeSpan'
when DATA_TYPE = 'timestamp' then 'DateTime'
when DATA_TYPE = 'tinyint' then 'byte'
when DATA_TYPE = 'uniqueidentifier' then 'Guid'
when DATA_TYPE = 'varbinary' then 'byte[]'
when DATA_TYPE = 'varchar' then 'string'
else '_UNKNOWN_'
end, ' ',
COLUMN_NAME, ' {get; set;}') as property_
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = @table AND table_schema = @schema) a
;
谢谢Alex和Guilherme!
Postgres DB -> c#的另一个解决方案
兼容NpgSQL 添加DataAnnotations
SELECT
CASE
WHEN c.is_nullable ='NO' THEN '[Required]'||chr(10)
ELSE '' END
||CASE
WHEN c.data_type = 'character varying' THEN format('[StringLength(%s)]',c.character_maximum_length)||chr(10)
ELSE '' END
||'public '
||CASE
WHEN c.data_type = 'integer' THEN 'int'
WHEN c.data_type = 'boolean' THEN 'bool'
WHEN c.data_type = 'double precision' THEN 'double'
WHEN c.data_type = 'uuid' THEN 'Guid'
WHEN c.data_type = 'character varying' THEN 'string'
WHEN c.data_type = 'timestamp without time zone' THEN 'DateTime'
WHEN c.data_type = 'bigint' THEN 'long'
WHEN c.data_type = 'bytea' THEN 'byte[]'
ELSE 'object' END
||CASE
WHEN c.is_nullable='YES' AND NOT c.data_type = 'character varying' THEN '? '
ELSE ' ' END
||c.column_name||' {get;set;}'
,c.*
FROM information_schema."columns" c
WHERE 1=1
AND c.table_name='YOUR_TABLE_NAME'
有点晚了，但我已经创建了一个web工具来帮助创建一个c#(或其他)对象从SQL结果，SQL表和SQL SP。
sql2object.com
这可以让你安全地输入所有的属性和类型。
如果无法识别类型，则将选择默认类型。
这篇文章救了我好几次。我只是想补充我的意见。 对于那些不喜欢使用orm，而是编写自己的DAL类的人来说，当你在一个表中有20个列，40个不同的表有各自的CRUD操作时，这是痛苦和浪费时间的。我重复了上面的代码，用于基于表实体和属性生成CRUD方法。
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 '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 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
declare @InitDataAccess varchar(max) = 'public class '+ @TableName +'DataAccess
{ '
declare @ListStatement varchar(max) ='public List<'+@TableName+'> Get'+@TableName+'List()
{
String conn = ConfigurationManager.ConnectionStrings["ConnectionNameInWeb.config"].ConnectionString;
var itemList = new List<'+@TableName+'>();
try
{
using (var sqlCon = new SqlConnection(conn))
{
sqlCon.Open();
var cmd = new SqlCommand
{
Connection = sqlCon,
CommandType = CommandType.StoredProcedure,
CommandText = "StoredProcedureSelectAll"
};
SqlDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
var item = new '+@TableName+'();
'
select @ListStatement = @ListStatement + '
item.'+ ColumnName + '= ('+ ColumnType + NullableSign +')reader["'+ColumnName+'"];
'
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 '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 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
select @ListStatement = @ListStatement +'
itemList.Add(item);
}
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
return itemList;
}'
declare @GetIndividual varchar(max) =
'public '+@TableName+' Get'+@TableName+'()
{
String conn = ConfigurationManager.ConnectionStrings["ConnectionNameInWeb.config"].ConnectionString;
var item = new '+@TableName+'();
try
{
using (var sqlCon = new SqlConnection(conn))
{
sqlCon.Open();
var cmd = new SqlCommand
{
Connection = sqlCon,
CommandType = CommandType.StoredProcedure,
CommandText = "StoredProcedureSelectIndividual"
};
cmd.Parameters.AddWithValue("@ItemCriteria", item.id);
SqlDataReader reader = cmd.ExecuteReader();
if (reader.Read())
{'
select @GetIndividual = @GetIndividual + '
item.'+ ColumnName + '= ('+ ColumnType + NullableSign +')reader["'+ColumnName+'"];
'
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 '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 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
select @GetIndividual = @GetIndividual +'
}
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
return item;
}'
declare @InsertStatement varchar(max) = 'public void Insert'+@TableName+'('+@TableName+' item)
{
String conn = ConfigurationManager.ConnectionStrings["ConnectionNameInWeb.config"].ConnectionString;
try
{
using (var sqlCon = new SqlConnection(conn))
{
sqlCon.Open();
var cmd = new SqlCommand
{
Connection = sqlCon,
CommandType = CommandType.StoredProcedure,
CommandText = "StoredProcedureInsert"
};
'
select @InsertStatement = @InsertStatement + '
cmd.Parameters.AddWithValue("@'+ColumnName+'", item.'+ColumnName+');
'
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 '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 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
select @InsertStatement = @InsertStatement +'
cmd.ExecuteNonQuery();
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}'
declare @UpdateStatement varchar(max) = 'public void Update'+@TableName+'('+@TableName+' item)
{
String conn = ConfigurationManager.ConnectionStrings["ConnectionNameInWeb.config"].ConnectionString;
try
{
using (var sqlCon = new SqlConnection(conn))
{
sqlCon.Open();
var cmd = new SqlCommand
{
Connection = sqlCon,
CommandType = CommandType.StoredProcedure,
CommandText = "StoredProcedureUpdate"
};
cmd.Parameters.AddWithValue("@UpdateCriteria", item.Id);
'
select @UpdateStatement = @UpdateStatement + '
cmd.Parameters.AddWithValue("@'+ColumnName+'", item.'+ColumnName+');
'
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 '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 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
select @UpdateStatement = @UpdateStatement +'
cmd.ExecuteNonQuery();
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
}'
declare @EndDataAccess varchar(max) = '
}'
print @InitDataAccess
print @GetIndividual
print @InsertStatement
print @UpdateStatement
print @ListStatement
print @EndDataAccess
当然它不是防弹代码，并且可以改进。只是想为这个优秀的解决方案做点贡献
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。
