Updates information in the database.

Updates information in the database.
Author:Www.gudianxiaoshuo.com


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Method 1: use SQL statements

Update a column

StrCmd. format (_ T ("update classInfo set class ID = % d where ID = % d"), iClassID, iClassID); spCmd-> CommandText = (LPCTSTR) strCmd; spCmd-> Execute (NULL, NULL, ad1_text );

Multiple update columns are separated by commas (,).

UPDATE Person SET Address = 'Zhongshan 23', City = 'Nanjing'WHERE LastName = 'Wilson'

Multiple batch updates

Try {CString strCmd; _ CommandPtr spCmd; spCmd. createInstance (_ uuidof (Command); spCmd-> ActiveConnection = m_pConnection; int nCount = random (); CString ruxuenianStr; CString banjiStr; CString xueqiStr; for (int nIndex = 0; nIndex <nCount; nIndex ++) {ruxuenianStr = random (nIndex, 1); banjiStr = m_BanjiList.GetItemText (nIndex, 2); xueqiStr = random (nIndex, 3); strCmd. format (_ T ("update ClassInfo set name = % d where admission year = % d and class = \" % s \ "and semester = \" % s \""), explain (nIndex), _ ttoi (ruxuenianStr), banjiStr, xueqiStr); spCmd-> CommandText = (LPCTSTR) strCmd; spCmd-> Execute (NULL, NULL, ad1_text );}} catch (_ com_error & e) {AfxMessageBox (e. error ());}

// Update the student ID CString strCmd; strCmd in the class table in batches. format (_ T ("SELECT * FROM class Table % d order by student ID"), m_pParentStudentInfo-> m_nClassID); pRecordSet-> Open (_ variant_t) strCmd, m_pConnection.GetInterfacePtr (), adOpenDynamic, adLockOptimistic, adshorttext); {pRecordSet-> MoveLast (); int nNew = 0; while (! PRecordSet-> adoBOF) {varValue = pRecordSet-> GetCollect (_ T ("student ID"); if (varValue. vt! = VT_NULL) {nStuXuehao = _ ttoi (LPCTSTR) _ bstr_t (varValue); // nNew = id_Map [nStuXuehao]; pRecordSet-> PutCollect (_ T ("student ID"), (long)-nStuXuehao); pRecordSet-> MovePrevious () ;}} pRecordSet-> UpdateBatch (adAffectAll );}

Method 2: Use AddNew Update

_ RecordsetPtr pRecordSet; CString strCmd; pRecordSet. createInstance (_ uuidof (Recordset); strCmd. format (_ T ("SELECT * FROM class Table % d where student ID = % d"), \ locate the record to be modified m_pParentStudentInfo-> m_nClassID, nXuehao ); pRecordSet-> Open (_ variant_t) strCmd, m_pConnection.GetInterfacePtr (), adOpenDynamic, adLockOptimistic, adCmdText); // pRecordSet-> AddNew (); add new records using AddNew, modify records, delete this statement pRecordSet-> PutCollect (_ T ("student ID"), (long) nXuehao); pRecordSet-> PutCollect (_ T ("name"), (LPCTSTR) nameStr); pRecordSet-> PutCollect (_ T ("gender"), (LPCTSTR) sexStr); pRecordSet-> PutCollect (_ T ("Address"), (LPCTSTR) addStr); pRecordSet-> PutCollect (_ T ("contact information"), (LPCTSTR) lianxiStr); pRecordSet-> PutCollect (_ T ("Remarks"), (LPCTSTR) beizhuStr); CFile f; CFileException e; if (f. open (zhaoPianStr, CFile: modeRead | CFile: typeBinary, & e) // Open a jpg file {int nSize = f. getLength (); // first obtain the jpg file Length BYTE * pBuffer = new BYTE [nSize]; // apply for a memory on the heap based on the file size if (f. read (pBuffer, nSize)> 0) // Read the jpg file to pBuffer (applying for a block of memory on the stack) {BYTE * pBuf = pBuffer; /// the main section below is to put the jpg data in pBuffer into the database VARIANT varBLOB; SAFEARRAY * psa; SAFEARRAYBOUND rgsabound [1]; if (pBuf) {rgsabound [0]. lLbound = 0; rgsabound [0]. cElements = nSize; psa = SafeArrayCreate (VT_UI1, 1, rgsabound); for (long I = 0; I <(long) nSize; I ++) SafeArrayPutElement (psa, & I, pBuf ++); varBLOB. vt = VT_ARRAY | VT_UI1; varBLOB. parray = psa; pRecordSet-> GetFields ()-> GetItem (_ T ("photo")-> AppendChunk (varBLOB);} delete [] pBuffer; pBuf = NULL ;} f. close () ;}precordset-> Update (); // Update this record pRecordSet-> Close (); // Update this student to strCmd in the curriculum. format (_ T ("SELECT * FROM classroom sequence table % d where student ID = % d"), m_pParentStudentInfo-> m_nXueqiID, nXuehao); pRecordSet-> Open (_ variant_t) strCmd, m_pConnection.GetInterfacePtr (), adOpenDynamic, adLockOptimistic, adshorttext); pRecordSet-> PutCollect (_ T ("student ID"), (long) nXuehao ); pRecordSet-> PutCollect (_ T ("name"), (LPCTSTR) nameStr); pRecordSet-> Update (); _ RecordsetPtr pRecordSet; CString strCmd; pRecordSet. createInstance (_ uuidof (Recordset); // update the student to strCmd in the course list. format (_ T ("SELECT * FROM classroom sequence table % d where student ID = % d"), m_pParentStudentInfo-> m_nXueqiID, nOldXuehao); pRecordSet-> Open (_ variant_t) strCmd, m_pConnection.GetInterfacePtr (), adOpenDynamic, adLockOptimistic, adshorttext); pRecordSet-> PutCollect (_ T ("name"), (LPCTSTR) nameStr); pRecordSet-> Update (); pRecordSet-> Close ();