乱序读取列 returns 不正确的值（SQL 服务器 ODBC 驱动程序）
Reading columns out of order returns incorrect values (SQL Server ODBC driver)
This question is part in a series of bugs in the Microsoft ODBC
driver:
- ODBC driver fails to raise errors; but instead suppresses them
- Cannot execute a stored procedure that is a SYNONYM
Microsoft has said they will not be fixing these bugs in their ODBC
driver.
精简版
如果我在 SELECT 订单中读取 uniqueidentifier 值，我会 return 编辑正确的值：
- ColumnB: (读取有效值)
- ColumnC (读取有效值)
如果我在 select 顺序之外读取 uniqueidentifier 列值，则较早的列 return 没有任何内容（有时是垃圾）：
- ColumnC (读取有效值)
- ColumnB (return为空)
我测试过：
- 微软 SQL Azure (RTM) - 12.0.2000.8
- 微软 SQL 服务器 2012 (SP3)
- 微软SQL服务器 2008 R2 (SP2)
- 微软 SQL Server 2005 - 9.00.5000.00 (Intel X86)
- Windows 10
- Windows 7
- WindowsVista
编辑：提供的代码示例：
- C# （命令行应用程序）
- Delphi （命令行应用程序）
- Javascript（命令行
cscript）
- Html+Javascript （仅限 Internet Explorer）
背景
使用 the announcement of the deprecation of OleDb drivers，我想测试使用 SQL 服务器的 ODBC 驱动程序。当我更改连接以使用 SQL 服务器 ODBC 驱动程序之一（例如“{SQL 服务器}”）并执行相同的 SQL 语句时。
更新 - 未弃用：六年后，微软 announced the un-deprecation the SQL Server OLE DB driver. (archive)
Previously, Microsoft announced deprecation of the Microsoft OLE DB Provider for SQL Server, part of the SQL Server Native Client (SNAC). At the time, this decision was made to try to provide more simplicity for the developer story around Windows native software development as we moved into the cloud era with Azure SQL Database, and to try to leverage the similarities of JDBC and ODBC for developers. However, during subsequent reviews it was determined that deprecation was a mistake because substantial scenarios within SQL Server still depend on OLE DB and changing those would break some existing customer scenarios.
With this in mind, we have decided to undeprecate OLE DB and release a new version by the first quarter of calendar year 2018 March 2018.
我正在为三个固定列发出查询：
SELECT
CAST('Hello' AS varchar(max)) AS ColumnA,
CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB,
CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC
这意味着有三列：
| ColumnA | ColumnB | ColumnC |
| varchar(max) | uniqueidentifier | uniqueidentifier |
|--------------------|--------------------------------------|--------------------------------------|
| 'Hello' | C6705EDE-CE58-4AB9-81BE-679AC1E75DE6 | 2466C151-88EC-40C0-B091-25B6BD74070C |
Note: Obviously when i discovered the bug i was selecting real data from a real table. In my quest to create a MRCE found the above database-agnostic query also triggers the failure.
我正在使用 ADO（本机 COM）和 SQL 服务器 ODBC 驱动程序连接到 SQL 服务器：
Provider=MSDASQL;Driver={SQL Server};Server={vader};Database=master;Trusted_Connection=Yes;
首先读取 C 列导致 ColumnB 为空
在这个 MRCE 中，我只读取两个 uniqueidentifier 列的值。
recordset.Fields['ColumnB'].Value;
recordset.Fields['ColumnC'].Value;
如果我按 的顺序 阅读两列，结果是正确的：
- 列 B：
"C6705EDE-CE58-4AB9-81BE-679AC1E75DE6"（变体类型 VT_BSTR）
- 列 C：
"2466C151-88EC-40C0-B091-25B6BD74070C"（变体类型 VT_BSTR）
但如果我以其他顺序读取列值：
- 列 C：
"2466C151-88EC-40C0-B091-25B6BD74070C"（变体类型 VT_BSTR）
- 列 B：
(empty)（变体类型 VT_EMPTY）
最小代码示例 (C#)
using System;
namespace ConsoleApp1
{
class Program
{
static void Main(string[] args)
{
TestIt();
}
private static void TestIt()
{
String serverName = "vader";
String CRLF = "\r\n";
String connectionString = "Provider=MSDASQL;Driver={SQL Server};Server={" + serverName + "};Database=master;Trusted_Connection=Yes;";
WriteLn("ConnectionString: " + connectionString);
WriteLn("");
Int32 adOpenForwardOnly = 0;
Int32 adLockReadOnly = 1;
Int32 adCmdText = 1;
dynamic rs = CreateOleObject("ADODB.Recordset");
String sql = "SELECT " + CRLF +
" CAST('Hello' AS varchar(max)) AS ColumnA, " + CRLF +
" CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB," + CRLF +
" CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC";
WriteLn("Command text:");
WriteLn(sql);
WriteLn("");
WriteLn("Executing query");
rs.open(sql, connectionString, adOpenForwardOnly, adLockReadOnly, adCmdText);
WriteLn("Query complete");
if (rs.EOF) return; //just to shut people up
var columnC = rs("ColumnC").Value;
var columnB = rs("ColumnB").Value;
WriteLn("ColumnB: " + columnB);
WriteLn("ColumnC: " + columnC);
}
private static dynamic CreateOleObject(string progID)
{
Type comType = Type.GetTypeFromProgID(progID);
var instance = Activator.CreateInstance(comType);
return instance;
}
private static void WriteLn(string v)
{
Console.WriteLine(v);
}
}
}
结果：
ConnectionString: Provider=MSDASQL;Driver={SQL Server};Server={vader};Database=master;Trusted_Connection=Yes;
Command text:
SELECT
CAST('Hello' AS varchar(max)) AS ColumnA,
CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB,
CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC
Executing query
Query complete
ColumnB:
ColumnC: {2466C151-88EC-40C0-B091-25B6BD74070C}
最小代码示例 (Delphi)
program Project3;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils,
ADOInt,
ComObj,
ActiveX;
function DataTypeEnumToStr(t: DataTypeEnum): string;
begin
case t of
adEmpty: Result := 'adEmpty';
adSmallInt: Result := 'adSmallInt';
adInteger: Result := 'adInteger';
adTinyInt: Result := 'adTinyInt';
adBigInt: Result := 'adBigInt';
adUnsignedTinyInt: Result := 'adUnsignedTinyInt';
adUnsignedSmallInt: Result := 'adUnsignedSmallInt';
adUnsignedInt: Result := 'adUnsignedInt';
adUnsignedBigInt: Result := 'adUnsignedBigInt';
adSingle: Result := 'adSingle';
adDouble: Result := 'adDouble';
adCurrency: Result := 'adCurrency';
adDecimal: Result := 'adDecimal';
adNumeric: Result := 'adNumeric';
adBoolean: Result := 'adBoolean';
adError: Result := 'adError';
adUserDefined: Result := 'adUserDefined';
adVariant: Result := 'adVariant';
adIDispatch: Result := 'adIDispatch';
adIUnknown: Result := 'adIUnknown';
adGUID: Result := 'adGUID';
adDate: Result := 'adDate';
adDBDate: Result := 'adDBDate';
adDBTime: Result := 'adDBTime';
adDBTimeStamp: Result := 'adDBTimeStamp';
adBSTR: Result := 'adBSTR';
adChar: Result := 'adChar';
adVarChar: Result := 'adVarChar';
adLongVarChar: Result := 'adLongVarChar';
adWChar: Result := 'adWChar';
adVarWChar: Result := 'adVarWChar';
adLongVarWChar: Result := 'adLongVarWChar';
adBinary: Result := 'adBinary';
adVarBinary: Result := 'adVarBinary';
adLongVarBinary: Result := 'adLongVarBinary';
adChapter: Result := 'adChapter';
adFileTime: Result := 'adFileTime';
adDBFileTime: Result := 'adDBFileTime';
adPropVariant: Result := 'adPropVariant';
adVarNumeric: Result := 'adVarNumeric';
adArray: Result := 'adArray';
else
Result := IntToStr(t);
end;
end;
procedure TestLoadingGUID;
var
connectionString: string;
sql: string;
rs: _Recordset;
s: string;
guid: TGUID;
i: Integer;
fld: Field;
function DumpField(const FieldName: string): string;
var
sValue: string;
vt: TVarType;
value: OleVariant;
begin
WriteLn('Reading '+FieldName+' column');
value := rs.Fields[FieldName].Value;
sValue := value;
vt := TVarData(value).VType;
WriteLn(' VType: '+IntToStr(vt));
WriteLn(' Value: "'+sValue+'" (as string)');
WriteLn('');
end;
begin
{
Tested:
Windows 10
Windows 7
Microsoft SQL Server 2012 (SP3)
Microsoft SQL Server 2008 R2 (SP2)
Microsoft SQL Server 2005 - 9.00.5000.00 (Intel X86)
}
Write('Enter name of server to connect to (leave blank for VADER): ');
ReadLn(s);
if s = '' then
s := 'vader';
connectionString := 'Provider=MSDASQL;Driver={SQL Server};Server={'+s+'};Database=master;Trusted_Connection=Yes;';
WriteLn('ConnectionString: '+connectionString);
WriteLn;
// sql := 'SELECT CAST(NULL AS varchar(max)) AS ColumnA, newid() AS ColumnB, newid() as ColumnC';
sql := 'SELECT '+#13#10+
' CAST(''Hello'' AS varchar(max)) AS ColumnA, '+#13#10+
' CAST(''C6705EDE-CE58-4AB9-81BE-679AC1E75DE6'' AS uniqueidentifier) AS ColumnB,'+#13#10+
' CAST(''2466C151-88EC-40C0-B091-25B6BD74070C'' AS uniqueidentifier) AS ColumnC';
rs := CoRecordset.Create;
rs.Open(sql, connectionString, adOpenForwardOnly, adLockReadOnly, adCmdText);
WriteLn('');
WriteLn('Command text: ');
WriteLn(sql);
WriteLn;
if rs.EOF then Exit; //just to shut people up
WriteLn('Recordset Fields');
for i := 0 to rs.Fields.Count-1 do
begin
fld := rs.Fields[i];
if fld.DefinedSize = MaxInt then
WriteLn(Format(' %d. %s: %s(%s)', [i, fld.Name, DataTypeEnumToStr(fld.Type_), 'max']))
else
WriteLn(Format(' %d. %s: %s(%d)', [i, fld.Name, DataTypeEnumToStr(fld.Type_), fld.DefinedSize]));
end;
WriteLn('');
WriteLn('');
WriteLn('Fields["ColumnA"]: "'+rs.Fields['ColumnA'].Value+'" (VType: '+IntToStr(TVarData(rs.Fields['ColumnA'].Value).VType)+')');
WriteLn('Fields["ColumnC"]: "'+rs.Fields['ColumnC'].Value+'" (VType: '+IntToStr(TVarData(rs.Fields['ColumnC'].Value).VType)+')');
WriteLn('Fields["ColumnB"]: "'+rs.Fields['ColumnB'].Value+'" (VType: '+IntToStr(TVarData(rs.Fields['ColumnB'].Value).VType)+')');
WriteLn('');
WriteLn('Fields[0]: "'+rs.Fields[0].Value+'" (VType: '+IntToStr(TVarData(rs.Fields[0].Value).VType)+')');
WriteLn('Fields[2]: "'+rs.Fields[2].Value+'" (VType: '+IntToStr(TVarData(rs.Fields[2].Value).VType)+')');
WriteLn('Fields[1]: "'+rs.Fields[1].Value+'" (VType: '+IntToStr(TVarData(rs.Fields[1].Value).VType)+')');
WriteLn('');
DumpField('ColumnA');
DumpField('ColumnB');
s := DumpField('ColumnC');
if s = '' then
begin
WriteLn(Format('WARNING: ColumnB expected to not-empty, but was "%s"', [s]));
Exit;
end;
end;
begin
try
CoInitialize(nil);
TestLoadingGUID;
except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;
WriteLn('Press enter to close');
Readln;
end.
和控制台输出
Enter name of server to connect to (leave blank for VADER):
ConnectionString: Provider=MSDASQL;Driver={SQL Server};Server={vader};Database=master;Trusted_Connection=Yes;
Command text:
SELECT
CAST('Hello' AS varchar(max)) AS ColumnA,
CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB,
CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC
Recordset Fields
0. ColumnA: adLongVarChar(max)
1. ColumnB: adGUID(16)
2. ColumnC: adGUID(16)
Fields["ColumnA"]: "Hello" (VType: 1)
Fields["ColumnC"]: "{2466C151-88EC-40C0-B091-25B6BD74070C}" (VType: 8)
Fields["ColumnB"]: "" (VType: 0)
Fields[0]: "" (VType: 0)
Fields[2]: "{2466C151-88EC-40C0-B091-25B6BD74070C}" (VType: 8)
Fields[1]: "" (VType: 0)
Reading ColumnA column
VType: 0
Value: "" (as string)
Reading ColumnB column
VType: 0
Value: "" (as string)
Reading ColumnC column
VType: 8
Value: "{2466C151-88EC-40C0-B091-25B6BD74070C}" (as string)
WARNING: ColumnB expected to not-empty, but was ""
Press enter to close
最小代码示例 (Javascript)
为了扩大受众范围，下面是 javascript 中的相同代码：
OdbcFails.js
main();
function main() {
serverName = "vader";
CRLF = "\r\n";
var connectionString = "Provider=MSDASQL;Driver={SQL Server};Server={"+serverName+"};Database=master;Trusted_Connection=Yes;";
WriteLn("ConnectionString: "+connectionString);
WriteLn("");
adOpenForwardOnly = 0;
adLockReadOnly = 1;
adCmdText = 1;
var rs = new ActiveXObject("ADODB.Recordset");
var sql = "SELECT "+CRLF+
" CAST('Hello' AS varchar(max)) AS ColumnA, "+CRLF+
" CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB,"+CRLF+
" CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC";
WriteLn("Command text:");
WriteLn(sql);
WriteLn("");
WriteLn("Executing query");
rs.open(sql, connectionString, adOpenForwardOnly, adLockReadOnly, adCmdText);
WriteLn("Query complete");
if (rs.EOF) return; //just to shut people up
var columnC = rs("ColumnC").Value;
var columnB = rs("ColumnB").Value;
WriteLn("ColumnB: "+columnB);
WriteLn("ColumnC: "+columnC);
}
function WriteLn(str) {
WScript.Echo(str);
}
如果你 运行:
C:\Users\ian>cscript OdbcFails.js
Microsoft (R) Windows Script Host Version 5.812
Copyright (C) Microsoft Corporation. All rights reserved.
ConnectionString: Provider=MSDASQL;Driver={SQL Server};Server={vader};Database=master;Trusted_Connection=Yes;
Command text:
SELECT
CAST('Hello' AS varchar(max)) AS ColumnA,
CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB,
CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC
Executing query
Query complete
ColumnB: undefined
ColumnC: {2466C151-88EC-40C0-B091-25B6BD74070C}
最小代码示例（html+javascript - 仅限 Internet Explorer）
<!doctype html>
<html>
<head>
<script>
function WriteLn(str) {
console.log(str);
}
function main() {
serverName = "vader";
CRLF = "\r\n";
var connectionString = "Provider=MSDASQL;Driver={SQL Server};Server={" + serverName + "};Database=master;Trusted_Connection=Yes;";
WriteLn("ConnectionString: " + connectionString);
WriteLn("");
adOpenForwardOnly = 0;
adLockReadOnly = 1;
adCmdText = 1;
var rs = new ActiveXObject("ADODB.Recordset");
var sql = "SELECT " + CRLF +
" CAST('Hello' AS varchar(max)) AS ColumnA, " + CRLF +
" CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB," + CRLF +
" CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC";
WriteLn("Command text:");
WriteLn(sql);
WriteLn("");
WriteLn("Executing query");
rs.open(sql, connectionString, adOpenForwardOnly, adLockReadOnly, adCmdText);
WriteLn("Query complete");
if (rs.EOF) return; //just to shut people up
var columnC = rs("ColumnC").Value;
var columnB = rs("ColumnB").Value;
WriteLn("ColumnB: " + columnB);
WriteLn("ColumnC: " + columnC);
}
main();
</script>
<body>
</body>
<script>
红利阅读
- MSDN 博客：Microsoft is Aligning with ODBC for Native Relational Data Access (archive)
- ADO.Net 博客：Microsoft SQL Server OLEDB Provider Deprecation Announcement (archive)
- MSDN：Converting SQL Server Applications from OLE DB to ODBC (archive)
- HAL2020: OLE DB and SQL Server: History, End-Game, and some Microsoft “dirt” (archive)
- MSDN 论坛：Invalid Descriptor Index calling SQLGetData (archive)
- IBM：DataStage job with ODBC Connector receives an error when using LOB Column (archive)
答案是 ODBC 驱动程序不会修复此行为。
在 1980 年代后期，强制客户端仅按顺序从行缓冲区中读取列具有性能优势。您会询问驱动程序是否允许您通过 SqlGetInfo function:
以任何顺序读取列值
SqlGetInfo(..., SQL_GD_ANY_ORDER, ...) //returns true or false
SQL_GD_ANY_COLUMN = SQLGetData 可以为任何未绑定的列调用，包括最后一个绑定列之前的列。请注意，必须按列号升序调用列，除非还返回 SQL_GD_ANY_ORDER。SQL_GD_ANY_ORDER = SQLGetData 可以按任何顺序为未绑定的列调用。请注意 SQLGetData 只能为最后一个绑定列之后的列调用，除非还返回 SQL_GD_ANY_COLUMN。
即使现在的计算机有超过 4MB 的 RAM，来自 Windows 3.0 时代的现代 SQL 服务器 ODBC 驱动程序 continues to opt-in to this limitation：
The SQL Server Native Client ODBC driver does not support using SQLGetData to retrieve data in random column order.
他们很好可以支持这样的东西，就像 17 年前的 OLEDB 驱动程序，以及 ADO.NET SqlClient 驱动程序一样。但他们没有；因此 ODBC 驱动程序是不适合实际使用的脑死亡可憎的东西。
您需要继续使用：
- SQLOLEDB (supported)
- SQLNCLI（已弃用）
- ADO.net SqlClient（支持）
红利阅读
Client Driver Support Policies
- OLE DB Support Policies: Applications should use the SQL Server OLE DB provider included with the Windows operating system.
- ADO Support Policies: ADO applications can use the SQLOLEDB OLE DB provider that is included with Windows if they do not require any of the features of SQL Server 2005 or later.
This question is part in a series of bugs in the Microsoft ODBC driver:
- ODBC driver fails to raise errors; but instead suppresses them
- Cannot execute a stored procedure that is a SYNONYM
Microsoft has said they will not be fixing these bugs in their ODBC driver.
精简版
如果我在 SELECT 订单中读取 uniqueidentifier 值，我会 return 编辑正确的值：
- ColumnB: (读取有效值)
- ColumnC (读取有效值)
如果我在 select 顺序之外读取 uniqueidentifier 列值，则较早的列 return 没有任何内容（有时是垃圾）：
- ColumnC (读取有效值)
- ColumnB (return为空)
我测试过：
- 微软 SQL Azure (RTM) - 12.0.2000.8
- 微软 SQL 服务器 2012 (SP3)
- 微软SQL服务器 2008 R2 (SP2)
- 微软 SQL Server 2005 - 9.00.5000.00 (Intel X86)
- Windows 10
- Windows 7
- WindowsVista
编辑：提供的代码示例：
- C# （命令行应用程序）
- Delphi （命令行应用程序）
- Javascript（命令行
cscript） - Html+Javascript （仅限 Internet Explorer）
背景
使用 the announcement of the deprecation of OleDb drivers，我想测试使用 SQL 服务器的 ODBC 驱动程序。当我更改连接以使用 SQL 服务器 ODBC 驱动程序之一（例如“{SQL 服务器}”）并执行相同的 SQL 语句时。
更新 - 未弃用：六年后，微软 announced the un-deprecation the SQL Server OLE DB driver. (archive)
Previously, Microsoft announced deprecation of the Microsoft OLE DB Provider for SQL Server, part of the SQL Server Native Client (SNAC). At the time, this decision was made to try to provide more simplicity for the developer story around Windows native software development as we moved into the cloud era with Azure SQL Database, and to try to leverage the similarities of JDBC and ODBC for developers. However, during subsequent reviews it was determined that deprecation was a mistake because substantial scenarios within SQL Server still depend on OLE DB and changing those would break some existing customer scenarios.
With this in mind, we have decided to undeprecate OLE DB and release a new version by
the first quarter of calendar year 2018March 2018.
我正在为三个固定列发出查询：
SELECT
CAST('Hello' AS varchar(max)) AS ColumnA,
CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB,
CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC
这意味着有三列：
| ColumnA | ColumnB | ColumnC |
| varchar(max) | uniqueidentifier | uniqueidentifier |
|--------------------|--------------------------------------|--------------------------------------|
| 'Hello' | C6705EDE-CE58-4AB9-81BE-679AC1E75DE6 | 2466C151-88EC-40C0-B091-25B6BD74070C |
Note: Obviously when i discovered the bug i was selecting real data from a real table. In my quest to create a MRCE found the above database-agnostic query also triggers the failure.
我正在使用 ADO（本机 COM）和 SQL 服务器 ODBC 驱动程序连接到 SQL 服务器：
Provider=MSDASQL;Driver={SQL Server};Server={vader};Database=master;Trusted_Connection=Yes;
首先读取 C 列导致 ColumnB 为空
在这个 MRCE 中，我只读取两个 uniqueidentifier 列的值。
recordset.Fields['ColumnB'].Value;
recordset.Fields['ColumnC'].Value;
如果我按 的顺序 阅读两列，结果是正确的：
- 列 B：
"C6705EDE-CE58-4AB9-81BE-679AC1E75DE6"（变体类型VT_BSTR） - 列 C：
"2466C151-88EC-40C0-B091-25B6BD74070C"（变体类型VT_BSTR）
但如果我以其他顺序读取列值：
- 列 C：
"2466C151-88EC-40C0-B091-25B6BD74070C"（变体类型VT_BSTR） - 列 B：
(empty)（变体类型VT_EMPTY）
最小代码示例 (C#)
using System;
namespace ConsoleApp1
{
class Program
{
static void Main(string[] args)
{
TestIt();
}
private static void TestIt()
{
String serverName = "vader";
String CRLF = "\r\n";
String connectionString = "Provider=MSDASQL;Driver={SQL Server};Server={" + serverName + "};Database=master;Trusted_Connection=Yes;";
WriteLn("ConnectionString: " + connectionString);
WriteLn("");
Int32 adOpenForwardOnly = 0;
Int32 adLockReadOnly = 1;
Int32 adCmdText = 1;
dynamic rs = CreateOleObject("ADODB.Recordset");
String sql = "SELECT " + CRLF +
" CAST('Hello' AS varchar(max)) AS ColumnA, " + CRLF +
" CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB," + CRLF +
" CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC";
WriteLn("Command text:");
WriteLn(sql);
WriteLn("");
WriteLn("Executing query");
rs.open(sql, connectionString, adOpenForwardOnly, adLockReadOnly, adCmdText);
WriteLn("Query complete");
if (rs.EOF) return; //just to shut people up
var columnC = rs("ColumnC").Value;
var columnB = rs("ColumnB").Value;
WriteLn("ColumnB: " + columnB);
WriteLn("ColumnC: " + columnC);
}
private static dynamic CreateOleObject(string progID)
{
Type comType = Type.GetTypeFromProgID(progID);
var instance = Activator.CreateInstance(comType);
return instance;
}
private static void WriteLn(string v)
{
Console.WriteLine(v);
}
}
}
结果：
ConnectionString: Provider=MSDASQL;Driver={SQL Server};Server={vader};Database=master;Trusted_Connection=Yes;
Command text:
SELECT
CAST('Hello' AS varchar(max)) AS ColumnA,
CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB,
CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC
Executing query
Query complete
ColumnB:
ColumnC: {2466C151-88EC-40C0-B091-25B6BD74070C}
最小代码示例 (Delphi)
program Project3;
{$APPTYPE CONSOLE}
{$R *.res}
uses
System.SysUtils,
ADOInt,
ComObj,
ActiveX;
function DataTypeEnumToStr(t: DataTypeEnum): string;
begin
case t of
adEmpty: Result := 'adEmpty';
adSmallInt: Result := 'adSmallInt';
adInteger: Result := 'adInteger';
adTinyInt: Result := 'adTinyInt';
adBigInt: Result := 'adBigInt';
adUnsignedTinyInt: Result := 'adUnsignedTinyInt';
adUnsignedSmallInt: Result := 'adUnsignedSmallInt';
adUnsignedInt: Result := 'adUnsignedInt';
adUnsignedBigInt: Result := 'adUnsignedBigInt';
adSingle: Result := 'adSingle';
adDouble: Result := 'adDouble';
adCurrency: Result := 'adCurrency';
adDecimal: Result := 'adDecimal';
adNumeric: Result := 'adNumeric';
adBoolean: Result := 'adBoolean';
adError: Result := 'adError';
adUserDefined: Result := 'adUserDefined';
adVariant: Result := 'adVariant';
adIDispatch: Result := 'adIDispatch';
adIUnknown: Result := 'adIUnknown';
adGUID: Result := 'adGUID';
adDate: Result := 'adDate';
adDBDate: Result := 'adDBDate';
adDBTime: Result := 'adDBTime';
adDBTimeStamp: Result := 'adDBTimeStamp';
adBSTR: Result := 'adBSTR';
adChar: Result := 'adChar';
adVarChar: Result := 'adVarChar';
adLongVarChar: Result := 'adLongVarChar';
adWChar: Result := 'adWChar';
adVarWChar: Result := 'adVarWChar';
adLongVarWChar: Result := 'adLongVarWChar';
adBinary: Result := 'adBinary';
adVarBinary: Result := 'adVarBinary';
adLongVarBinary: Result := 'adLongVarBinary';
adChapter: Result := 'adChapter';
adFileTime: Result := 'adFileTime';
adDBFileTime: Result := 'adDBFileTime';
adPropVariant: Result := 'adPropVariant';
adVarNumeric: Result := 'adVarNumeric';
adArray: Result := 'adArray';
else
Result := IntToStr(t);
end;
end;
procedure TestLoadingGUID;
var
connectionString: string;
sql: string;
rs: _Recordset;
s: string;
guid: TGUID;
i: Integer;
fld: Field;
function DumpField(const FieldName: string): string;
var
sValue: string;
vt: TVarType;
value: OleVariant;
begin
WriteLn('Reading '+FieldName+' column');
value := rs.Fields[FieldName].Value;
sValue := value;
vt := TVarData(value).VType;
WriteLn(' VType: '+IntToStr(vt));
WriteLn(' Value: "'+sValue+'" (as string)');
WriteLn('');
end;
begin
{
Tested:
Windows 10
Windows 7
Microsoft SQL Server 2012 (SP3)
Microsoft SQL Server 2008 R2 (SP2)
Microsoft SQL Server 2005 - 9.00.5000.00 (Intel X86)
}
Write('Enter name of server to connect to (leave blank for VADER): ');
ReadLn(s);
if s = '' then
s := 'vader';
connectionString := 'Provider=MSDASQL;Driver={SQL Server};Server={'+s+'};Database=master;Trusted_Connection=Yes;';
WriteLn('ConnectionString: '+connectionString);
WriteLn;
// sql := 'SELECT CAST(NULL AS varchar(max)) AS ColumnA, newid() AS ColumnB, newid() as ColumnC';
sql := 'SELECT '+#13#10+
' CAST(''Hello'' AS varchar(max)) AS ColumnA, '+#13#10+
' CAST(''C6705EDE-CE58-4AB9-81BE-679AC1E75DE6'' AS uniqueidentifier) AS ColumnB,'+#13#10+
' CAST(''2466C151-88EC-40C0-B091-25B6BD74070C'' AS uniqueidentifier) AS ColumnC';
rs := CoRecordset.Create;
rs.Open(sql, connectionString, adOpenForwardOnly, adLockReadOnly, adCmdText);
WriteLn('');
WriteLn('Command text: ');
WriteLn(sql);
WriteLn;
if rs.EOF then Exit; //just to shut people up
WriteLn('Recordset Fields');
for i := 0 to rs.Fields.Count-1 do
begin
fld := rs.Fields[i];
if fld.DefinedSize = MaxInt then
WriteLn(Format(' %d. %s: %s(%s)', [i, fld.Name, DataTypeEnumToStr(fld.Type_), 'max']))
else
WriteLn(Format(' %d. %s: %s(%d)', [i, fld.Name, DataTypeEnumToStr(fld.Type_), fld.DefinedSize]));
end;
WriteLn('');
WriteLn('');
WriteLn('Fields["ColumnA"]: "'+rs.Fields['ColumnA'].Value+'" (VType: '+IntToStr(TVarData(rs.Fields['ColumnA'].Value).VType)+')');
WriteLn('Fields["ColumnC"]: "'+rs.Fields['ColumnC'].Value+'" (VType: '+IntToStr(TVarData(rs.Fields['ColumnC'].Value).VType)+')');
WriteLn('Fields["ColumnB"]: "'+rs.Fields['ColumnB'].Value+'" (VType: '+IntToStr(TVarData(rs.Fields['ColumnB'].Value).VType)+')');
WriteLn('');
WriteLn('Fields[0]: "'+rs.Fields[0].Value+'" (VType: '+IntToStr(TVarData(rs.Fields[0].Value).VType)+')');
WriteLn('Fields[2]: "'+rs.Fields[2].Value+'" (VType: '+IntToStr(TVarData(rs.Fields[2].Value).VType)+')');
WriteLn('Fields[1]: "'+rs.Fields[1].Value+'" (VType: '+IntToStr(TVarData(rs.Fields[1].Value).VType)+')');
WriteLn('');
DumpField('ColumnA');
DumpField('ColumnB');
s := DumpField('ColumnC');
if s = '' then
begin
WriteLn(Format('WARNING: ColumnB expected to not-empty, but was "%s"', [s]));
Exit;
end;
end;
begin
try
CoInitialize(nil);
TestLoadingGUID;
except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;
WriteLn('Press enter to close');
Readln;
end.
和控制台输出
Enter name of server to connect to (leave blank for VADER):
ConnectionString: Provider=MSDASQL;Driver={SQL Server};Server={vader};Database=master;Trusted_Connection=Yes;
Command text:
SELECT
CAST('Hello' AS varchar(max)) AS ColumnA,
CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB,
CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC
Recordset Fields
0. ColumnA: adLongVarChar(max)
1. ColumnB: adGUID(16)
2. ColumnC: adGUID(16)
Fields["ColumnA"]: "Hello" (VType: 1)
Fields["ColumnC"]: "{2466C151-88EC-40C0-B091-25B6BD74070C}" (VType: 8)
Fields["ColumnB"]: "" (VType: 0)
Fields[0]: "" (VType: 0)
Fields[2]: "{2466C151-88EC-40C0-B091-25B6BD74070C}" (VType: 8)
Fields[1]: "" (VType: 0)
Reading ColumnA column
VType: 0
Value: "" (as string)
Reading ColumnB column
VType: 0
Value: "" (as string)
Reading ColumnC column
VType: 8
Value: "{2466C151-88EC-40C0-B091-25B6BD74070C}" (as string)
WARNING: ColumnB expected to not-empty, but was ""
Press enter to close
最小代码示例 (Javascript)
为了扩大受众范围，下面是 javascript 中的相同代码：
OdbcFails.js
main();
function main() {
serverName = "vader";
CRLF = "\r\n";
var connectionString = "Provider=MSDASQL;Driver={SQL Server};Server={"+serverName+"};Database=master;Trusted_Connection=Yes;";
WriteLn("ConnectionString: "+connectionString);
WriteLn("");
adOpenForwardOnly = 0;
adLockReadOnly = 1;
adCmdText = 1;
var rs = new ActiveXObject("ADODB.Recordset");
var sql = "SELECT "+CRLF+
" CAST('Hello' AS varchar(max)) AS ColumnA, "+CRLF+
" CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB,"+CRLF+
" CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC";
WriteLn("Command text:");
WriteLn(sql);
WriteLn("");
WriteLn("Executing query");
rs.open(sql, connectionString, adOpenForwardOnly, adLockReadOnly, adCmdText);
WriteLn("Query complete");
if (rs.EOF) return; //just to shut people up
var columnC = rs("ColumnC").Value;
var columnB = rs("ColumnB").Value;
WriteLn("ColumnB: "+columnB);
WriteLn("ColumnC: "+columnC);
}
function WriteLn(str) {
WScript.Echo(str);
}
如果你 运行:
C:\Users\ian>cscript OdbcFails.js
Microsoft (R) Windows Script Host Version 5.812
Copyright (C) Microsoft Corporation. All rights reserved.
ConnectionString: Provider=MSDASQL;Driver={SQL Server};Server={vader};Database=master;Trusted_Connection=Yes;
Command text:
SELECT
CAST('Hello' AS varchar(max)) AS ColumnA,
CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB,
CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC
Executing query
Query complete
ColumnB: undefined
ColumnC: {2466C151-88EC-40C0-B091-25B6BD74070C}
最小代码示例（html+javascript - 仅限 Internet Explorer）
<!doctype html>
<html>
<head>
<script>
function WriteLn(str) {
console.log(str);
}
function main() {
serverName = "vader";
CRLF = "\r\n";
var connectionString = "Provider=MSDASQL;Driver={SQL Server};Server={" + serverName + "};Database=master;Trusted_Connection=Yes;";
WriteLn("ConnectionString: " + connectionString);
WriteLn("");
adOpenForwardOnly = 0;
adLockReadOnly = 1;
adCmdText = 1;
var rs = new ActiveXObject("ADODB.Recordset");
var sql = "SELECT " + CRLF +
" CAST('Hello' AS varchar(max)) AS ColumnA, " + CRLF +
" CAST('C6705EDE-CE58-4AB9-81BE-679AC1E75DE6' AS uniqueidentifier) AS ColumnB," + CRLF +
" CAST('2466C151-88EC-40C0-B091-25B6BD74070C' AS uniqueidentifier) AS ColumnC";
WriteLn("Command text:");
WriteLn(sql);
WriteLn("");
WriteLn("Executing query");
rs.open(sql, connectionString, adOpenForwardOnly, adLockReadOnly, adCmdText);
WriteLn("Query complete");
if (rs.EOF) return; //just to shut people up
var columnC = rs("ColumnC").Value;
var columnB = rs("ColumnB").Value;
WriteLn("ColumnB: " + columnB);
WriteLn("ColumnC: " + columnC);
}
main();
</script>
<body>
</body>
<script>
红利阅读
- MSDN 博客：Microsoft is Aligning with ODBC for Native Relational Data Access (archive)
- ADO.Net 博客：Microsoft SQL Server OLEDB Provider Deprecation Announcement (archive)
- MSDN：Converting SQL Server Applications from OLE DB to ODBC (archive)
- HAL2020: OLE DB and SQL Server: History, End-Game, and some Microsoft “dirt” (archive)
- MSDN 论坛：Invalid Descriptor Index calling SQLGetData (archive)
- IBM：DataStage job with ODBC Connector receives an error when using LOB Column (archive)
答案是 ODBC 驱动程序不会修复此行为。
在 1980 年代后期，强制客户端仅按顺序从行缓冲区中读取列具有性能优势。您会询问驱动程序是否允许您通过 SqlGetInfo function:
以任何顺序读取列值SqlGetInfo(..., SQL_GD_ANY_ORDER, ...) //returns true or false
SQL_GD_ANY_COLUMN= SQLGetData 可以为任何未绑定的列调用，包括最后一个绑定列之前的列。请注意，必须按列号升序调用列，除非还返回SQL_GD_ANY_ORDER。SQL_GD_ANY_ORDER= SQLGetData 可以按任何顺序为未绑定的列调用。请注意 SQLGetData 只能为最后一个绑定列之后的列调用，除非还返回SQL_GD_ANY_COLUMN。
即使现在的计算机有超过 4MB 的 RAM，来自 Windows 3.0 时代的现代 SQL 服务器 ODBC 驱动程序 continues to opt-in to this limitation：
The SQL Server Native Client ODBC driver does not support using SQLGetData to retrieve data in random column order.
他们很好可以支持这样的东西，就像 17 年前的 OLEDB 驱动程序，以及 ADO.NET SqlClient 驱动程序一样。但他们没有；因此 ODBC 驱动程序是不适合实际使用的脑死亡可憎的东西。
您需要继续使用：
- SQLOLEDB (supported)
- SQLNCLI（已弃用）
- ADO.net SqlClient（支持）
红利阅读
Client Driver Support Policies
- OLE DB Support Policies: Applications should use the SQL Server OLE DB provider included with the Windows operating system.
- ADO Support Policies: ADO applications can use the SQLOLEDB OLE DB provider that is included with Windows if they do not require any of the features of SQL Server 2005 or later.