如何使用TADOCommand参数化查询参数化宽字符串? [英] How to parameterize widestrings using TADOCommand parameterized query?
问题描述
我试图在Delphi TADOCommand中使用参数化查询:
i am trying to use a parameterized query with Delphi TADOCommand:
var
s: WideString;
cmd: TADOCommand;
recordsAffected: OleVariant;
begin
cmd := TADOCommand.Create(nil);
cmd.Connection := Connection;
cmd.CommandText := 'INSERT INTO Sqm(Filename) VALUES(:filename)';
s := AFilename;
cmd.Parameters.ParamByName('filename').Value := s;
cmd.Execute();
数据库中的结果数据已被完全破坏:
The resulting data in the database is complete mangled:
C?:\U?s?er?s?\i ?? n?.A?V`A?T?O?P?I?A?\ A?p?p?D ?? t ?? \L?o ??? l?\A?v?at ?? r? S?o?f?t?w?är¨? C?r ?? t?i ?? n?s?\S?o°f?t?w?r ?? Q?u ?? li?t?y? M ?? t?r?i?cs?\C ?? S?-s?q?m?00.x?m?l
C?:\U?s?er?s?\i??n?.A?V`A?T?O?P?I?A?\A?p?p?D??t??\L?o???l?\A?v?at??r? S?o?f?t?w?är¨? C?r??t?i??n?s?\S?o°f?t?w?r?? Q?u??li?t?y? M??t?r?i?cs?\C??S?-s?q?m?00.x?m?l
i 可以使用本机参数化的ADO Command
对象。它可以正确保存数据:
i can use a native parameterized ADO Command
object. It saves the data correctly:
C̬:\Ȗŝḙr͇s̶\i̜ẵn̥.ÀV̹AͧT̶O̠P̩I̿Ȁ\A͜p̥p̔D͑ẫt̒ā\L̫o͋ɕălͭ\A̼v̼ẵt͈ấr̄ S̫o̖f͎tͩw̬r͂ẽC͂ẽ \S̪ōf̒t͘w̚âr̿ɇQͬüẳlͮi̫tͥy̽M͘ȇt̨r̟i̻çš\C͍MͥS̚-s̞q̕m͜00.xͤm̧l̝
C̬:\Ȗŝḙr͇s̶\i̜ẵn̥.ÀV̹AͧT̶O̠P̩I̿Ȁ\A͜p̥p̔D͑ẫt̒ā\L̫o͋ɕălͭ\A̼v̼ẵt͈ấr̄ S̫o̖f͎t̻w̵ạr͂ẽ C̾r̮ḛẵt͘iͩo̳n̬s̨\S̪ōf̒t͘w̚âr̿ɇ Qͬüẳlͮi̫tͥy̽ M͘ȇt̨r̟i̻çš\C͍MͥS̚-s̞q̕m͜00.xͤm̧l̝
但这是非常脆弱,不适合用于生产用途。
我在Delphi中将unicode / WideStrings与 TADOCommand
一起使用?
How can i use unicode/WideStrings with TADOCommand
in Delphi?
奖励聊天
在SQL Server Profiler中,您可以看到正在执行的SQL:
In SQL Server Profiler you can see the SQL being executed:
exec sp_executesql N'插入Sqm(文件名)VALUES(@ P1)',N'@ P1 char(300),@ P2文本','C?:\Us?er?s?\i?än?.A?V? A?T?O?P?I?ÀA?p?p?D?a?L?o?çaléA?v?at?r?那么?f?w?ar ??? C?r ??á?i?o?n?s?\So¸f t?w?ar ?? Q?u ?? l?i?ty?M?t?r?i¸?s `\C?M°S?-s?q?m?00.?m¨'l'
exec sp_executesql N'INSERT INTO Sqm(Filename) VALUES(@P1)', N'@P1 char(300),@P2 text', 'C?:\Us?er?s?\i?än?.A?V?A?T?O?P?I?À\A?p?p?D?ât?a\L?o?çal¯\A?v?at??r? So?f?t?w?ar?? C?r??á?i?o?n?s?\So¸f"t?w?ar?? Q?u??l?i?ty? M??t?r?i¸?s`\C?M°S?-s?q?m?00.?m¨´l¯ '
哪个点解决了这个问题-它正在将 WideString
参数构建为 char(300)
的值。请确保它不会损坏。
Which points out the problem - it's building the WideString
parameter as a char(300)
value. Make it not broke.
在我的WideString降到参数孔之前的最后一次看到的是:
The last i see of my WideString before it goes down the parameter hole is:
ParameterObject.Value := NewValue;
其中
-
NewValue
是VT_BSTR
类型的变体(又名<$ c具有适当值的$ c> varOleStr ) -
ParameterObject
是本机ADO_Parameter
对象,并带有。类型
的129(adChar
)
NewValue
is a variant of typeVT_BSTR
(akavarOleStr
) with the proper valueParameterObject
is a native ADO_Parameter
object, with a.Type
of 129 (adChar
)
甚至试图强制参数类型:
Even trying to force the parameter type:
cmd.Parameters.ParamByName('filename').DataType := ftWideString;
cmd.Parameters.ParamByName('filename').Value := s;
没有帮助。
注意:这个问题是关于如何参数化
INSERT INTO foo(value)VALUES(%s)
的系列文章的一部分
Note: This question is part of a series on how to paramaterize
INSERT INTO foo (value) VALUES (%s)
- https://stackoverflow.com/questions/10726212/using-wrong-type-with-parameterized-query-causes-error
- 就ADO而言,nvarchar(max)有多大
- 如何使用TADOCommand参数化查询对宽字符串进行参数化?
- 必须声明变量@myvariable。 ADO参数化查询出现错误
- https://stackoverflow.com/questions/10726212/using-wrong-type-with-parameterized-query-causes-error
- How big is an nvarchar(max) as far as ADO is concerned?
- How to parameterize widestrings using TADOCommand parameterized query?
- "Must declare the variable @myvariable" error with ADO parameterized query
推荐答案
答案是,它不能在Delphi(5)中完成。
The answer is that it cannot be done in Delphi (5).
在更新的Delphi版本中可能已解决;但是如果没有任何人进行测试,我们将不会知道。
It might be fixed in newer versions of Delphi; but without anyone to test it we won't know.
问。:如何使用TADOCommand参数化查询对宽字符串进行参数化?
A。 :你不能。很抱歉给您带来不便。
Q.: How to parameterize widestrings using TADOCommand parameterized query?
A.: You can't. Sorry for the inconvience.
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