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更新 2

我打开了跟踪并运行了我的示例查询。这是痕迹。我确实看到了声明Strlen Or Ind = 0x7fff9c84ee88 -> 255。indicator变量定义为Is SQLLEN indicator;this not initialized proper?

[ODBC][22407][1379343424.503572][__handles.c][450]
        Exit:[SQL_SUCCESS]
            Environment = 0x14f8160
[ODBC][22407][1379343424.503627][SQLSetEnvAttr.c][182]
        Entry:            
            Environment = 0x14f8160            
            Attribute = SQL_ATTR_ODBC_VERSION            
            Value = 0x3            
            StrLen = 0
[ODBC][22407][1379343424.503654][SQLSetEnvAttr.c][349]
        Exit:[SQL_SUCCESS]
[ODBC][22407][1379343424.503678][SQLAllocHandle.c][364]
        Entry:
            Handle Type = 2
            Input Handle = 0x14f8160
[ODBC][22407][1379343424.503707][SQLAllocHandle.c][482]
        Exit:[SQL_SUCCESS]
            Output Handle = 0x14f8a90
[ODBC][22407][1379343424.503745][SQLDriverConnect.c][688]
        Entry:            
            Connection = 0x14f8a90            
            Window Hdl = (nil)            
            Str In = [DSN=MyDB;UID=MyUID;][length = 15 (SQL_NTS)]            
            Str Out = 0x7fff9c84cc80            
            Str Out Max = 2048            
            Str Out Ptr = (nil)            
            Completion = 1
        UNICODE Using encoding ASCII 'ISO8859-1' and UNICODE 'UCS-2LE'

[ODBC][22407][1379343424.523244][SQLDriverConnect.c][1497]
        Exit:[SQL_SUCCESS]                    
            Connection Out [[DSN=MyDB;UID=MyUID;][length = 15 (SQL_NTS)]]
[ODBC][22407][1379343424.523297][SQLAllocHandle.c][529]
        Entry:
            Handle Type = 3
            Input Handle = 0x14f8a90
[ODBC][22407][1379343424.523343][SQLAllocHandle.c][1064]
        Exit:[SQL_SUCCESS]
            Output Handle = 0x1526b40
[ODBC][22407][1379343424.523377][SQLExecDirect.c][236]
        Entry:            
            Statement = 0x1526b40            
            SQL = [SELECT '123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890...][length = 309 (SQL_NTS)]
[ODBC][22407][1379343424.523948][SQLExecDirect.c][499]
        Exit:[SQL_SUCCESS]
[ODBC][22407][1379343424.523982][SQLNumResultCols.c][152]
        Entry:            
            Statement = 0x1526b40            
            Column Count = 0x7fff9c84eeae
[ODBC][22407][1379343424.524005][SQLNumResultCols.c][244]
        Exit:[SQL_SUCCESS]                
            Count = 0x7fff9c84eeae -> 1
[ODBC][22407][1379343424.524030][SQLFetch.c][158]
        Entry:            
            Statement = 0x1526b40
[ODBC][22407][1379343424.524056][SQLFetch.c][340]
        Exit:[SQL_SUCCESS]
[ODBC][22407][1379343424.524084][SQLGetData.c][233]
        Entry:            
            Statement = 0x1526b40            
            Column Number = 1            
            Target Type = 1 SQL_CHAR            
            Buffer Length = 5000            
            Target Value = 0x7fff9c84da90            
            StrLen Or Ind = 0x7fff9c84ee88
[ODBC][22407][1379343424.524115][SQLGetData.c][497]
        Exit:[SQL_SUCCESS]                
            Buffer = [12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678]                
            Strlen Or Ind = 0x7fff9c84ee88 -> 255
[ODBC][22407][1379343424.524142][SQLColAttribute.c][286]
        Entry:            
            Statement = 0x1526b40            
            Column Number = 1            
            Field Identifier = SQL_DESC_NAME            
            Character Attr = 0x7fff9c84ee20            
            Buffer Length = 100            
            String Length = 0x7fff9c84ee86            
            Numeric Attribute = (nil)
[ODBC][22407][1379343424.524167][SQLColAttribute.c][657]
        Exit:[SQL_SUCCESS]
[ODBC][22407][1379343424.524229][SQLFetch.c][158]
        Entry:            
            Statement = 0x1526b40
[ODBC][22407][1379343424.524257][SQLFetch.c][340]
        Exit:[SQL_NO_DATA]
[ODBC][22407][1379343424.524321][SQLDisconnect.c][204]
        Entry:            
            Connection = 0x14f8a90
[ODBC][22407][1379343424.524375][SQLDisconnect.c][341]
        Exit:[SQL_SUCCESS]
[ODBC][22407][1379343424.524415][SQLFreeHandle.c][279]
        Entry:
            Handle Type = 2
            Input Handle = 0x14f8a90
[ODBC][22407][1379343424.524438][SQLFreeHandle.c][330]
        Exit:[SQL_SUCCESS]
[ODBC][22407][1379343424.524463][SQLFreeHandle.c][212]
        Entry:
            Handle Type = 1
            Input Handle = 0x14f8160

更新 我进一步调查了我的 C++ 程序。我现在看到查询结果在调用中被截断

data_ret = SQLGetData(stmt, i, SQL_C_CHAR, buf, sizeof(buf), &indicator);

buf长度足够且data_ret为零（成功）。我是在滥用SQLGetData，还是有一些我不知道的行为？

我见过其他人有类似的问题，但我还没有完全解决它。如果我查询一个长字符串，它会被截断为 255 个字符。我正在使用 unixODBC 和 FreeTDS 从 Linux 机器上的 bash 脚本查询 SQL Server DB。

我通过放置来设置驱动程序

[FreeTDS]
Description = v0.91 with protocol v7.2
Driver = /usr/lib64/libtdsodbc.so.0

在模板中并运行

odbcinst -i -d -f tds.driver.template

然后我把

[MyDB]
Driver = FreeTDS
Description = Database Description
Trace = No
Server = <serverIP>
Port = 1433
Database = <myDB>
UID = <myUID>

在模板中运行

odbcinst -i -s -f tds.datasource.template

我试过这个答案，但我一定做错了什么。任何建议表示赞赏。

4

1 回答 1

0

你没有说你用什么来从 shell 发出查询，但如果它是 isql，那么它会隐藏非常大的列并截断较小的列 - 可能是 255。

于 2013-09-10T15:21:59.607 回答