5,138,728 members and growing! (16,680 online)
Email Password   helpLost your password?
Database » Database » ADO     Intermediate

A set of ADO classes - version 2.20

By Carlos Antollini

Simple database access using an ADO class. 		SQL, VC6, C++Windows, NT4, Win2K, SQL, MFC, ADO, VS6, VS, DBA, Dev

Posted: 24 Apr 2001
Updated: 6 Sep 2005
Views: 1,087,197
Announcements
Services
Code Project Coffee
Free Magazines

Chapters
Desktop Development
Web Development
Enterprise Systems
Multimedia
Database
Platforms, Frameworks & Libraries
Languages
General Programming
Graphics / Design
Development Lifecycle
General Reading
Third Party Products

Feature Zones
IBM DeveloperWorks
WhitePapers
Code Generation
Quest SQL Zone
Search    
Advanced Search
Sitemap
print Print   Broken Article? Report Article       Discuss Discuss   Recommend Article Send to a friend
368 votes for this Article.
Popularity: 12.34 Rating: 4.81 out of 5
6 votes, 2.7%
1		 2 votes, 0.9%
2		 0 votes, 0.0%
3		 13 votes, 5.8%
4		 205 votes, 90.7%
5

Overview

Overview

I created these classes to make it easy to work with ADO. For this I created the CADODatabse class and the CADORecordset class.

The CADODatabase Class

The CADODatabase class has a set of functions that corresponds to the _ConnectionPtr.

CADODatabase::CADODatabase

Creates a CADODatabase object.

CADODatabase();

CADODatabase::Open

The Open function opens a connection to a database.

BOOL Open(LPCTSTR lpstrConnection = _T(""));
throw(CADOException);

Parameters

LPCTSTR lpstrConnection - The connection string.

See Sample

Note: the class has the function SetConnectionString. You can insert the connection string through this function. In this case you can do the following:

//Sample with Connection string for SQL Server


CADODatabase* pAdoDb = new CADODatabase();
CString strConnection = _T("");

strConnection = _T("Provider=MSDASQL;PersistSecurityInfo=False;"
                   "Trusted_Connection=Yes;"
                   "Data Source=Access Sql Server;catalog=sampledb");
pAdoDb->SetConnectionString(strConnection);

if(pAdoDb->Open())
  DoSomething();
.
.
.

//Sample with Connection String for Access database


CADODatabase* pAdoDb = new CADODatabase();
CString strConnection = _T("");

strConnection = _T("Provider=Microsoft.Jet.OLEDB.4.0;"
              "Data Source=C:\\VCProjects\\ADO\\Test\\dbTest.mdb");
pAdoDb->SetConnectionString(strConnection);

if(pAdoDb->Open())
{
  DoSomething();
  .
  .
  .
  pAdoDb->Close();
}

delete pAdoDb;

CADODatabase::Execute

The Execute function executes a SQL statement in the open database.

BOOL Execute(LPCTSTR lpstrExec);
throw(CADOException);

Parameters

LPCTSTR lpstrExec - A string pointer containing the SQL statement to execute.

CADODatabase* pAdoDb = new CADODatabase();
CString strConnection = _T("");

strConnection = _T("Provider=MSDASQL;"
                   "PersistSecurityInfo=False;"
                   "Trusted_Connection=Yes"
                "Data Source=Access Sql Server;catalog=sampledb");

if(pAdoDb->Open(strConnection))
 pAdoDb->Execute("Delete From tblClients Where Cheker = 3");

Return Value

The function returns TRUE if it was executed successfully.

CADODatabase::GetRecordsAffected

The GetRecordsAffcted function returns the number of records affected by the last SQL statement executed.

int GetRecordsAffected();

CADODatabase::GetActiveConnection

The GetActiveConnection returns the active connection.

_ConnectionPtr GetActiveConnection();

CADODatabase::GetRecordCount

GetRecordCount returns the number of records affected in a query.

DWORD GetRecordCount(_RecordsetPtr m_pRs);

Parameters

_RecorsetPtr m_Prs - The recordset.

CADODatabase::BeginTransaction

Call this function to initiate a transaction. After you call BeginTransaction, updates you make to your data take effect when you commit the transaction.

long BeginTransaction();

CADODatabase::CommitTransaction

Call CommitTransaction function to commit a transaction, for example, save a group of edits and updates to one or more databases.

long CommitTransaction();

CADODatabase::RollbackTransaction

Call RollbackTransaction function to end the current transaction and restore all databases to their condition before the transaction was begun.

long RollbackTransaction();

CADODatabase::IsOpen

The IsOpen function returns the status of the connection with the database.

BOOLIsOpen();

Return Value

The function returns TRUE if the connection to the database is open.

CADODatabase::Close

The Close function closes the connection to the database.

void Close();

CADODatabase::SetConnectionString

With the SetConnectionString, you can insert the connection string.

void SetConnectionString(LPCTSTR lpstrConnection);

Parameters

LPCTSTR lpstrConnection - A connection string used for opening the database.

See CADODatabase::Open();

CADODatabase::GetConnectionString

The GetConnectionString function returns the connection string used for making a connection with a database.

CString GetConnectionString();

CADODatabase::SetConnectionMode

The SetConnectionMode function sets the mode of connection.

void SetConnectionMode(cadoConnectModeEnum nMode);

Parameters

cadoConnectModeEnum nMode - a variable that defines the connection mode to be used. It can be one of the following:

  • CADODatabase::connectModeUnknown
  • CADODatabase::connectModeRead
  • CADODatabase::connectModeWrite
  • CADODatabase::connectModeReadWrite
  • CADODatabase::connectModeShareDenyRead
  • CADODatabase::connectModeShareDenyWrite
  • CADODatabase::connectModeShareExclusive
  • CADODatabase::connectModeShareDenyNone

CADODatabase::GetLastError

The GetLastError function returns the last error code.

DWORD GetLastError();

CADODatabase::GetLastErrorString

The GetLastErrorString function returns the last error string.

CString GetLastErrorString();

The CADORecordset Class

The CADORecordset class has a set of functions that corresponds to the _RecordsetPtr.

CADORecordset::CADORecordset

Creates a CADORecordset object.

CADODatabase();
CADORecordset(CADODatabase* pAdoDatabase);

Parameters

CADODatabase* pAdoDatabase - A CADODatabase object pointer.

CADORecordset::Open

The Open function opens a recordset.

BOOL Open(_ConnectionPtr mpdb, LPCTSTR lpstrExec = _T(""), 
                     int nOption = CADORecordset::openUnknown);
BOOL Open(LPCTSTR lpstrExec = _T(""), 
                     int nOption = CADORecordset::openUnknown);

Parameters

  • _ConnectionPtr mpdb - A connection pointer.
  • LPCTSTR lpstrExec - A string pointer containing an SQL SELECT statement.
  • int nOption - An integer that defines the access mode. The values are as follows:
    • CADORecordset::openUnknown
    • CADORecordset::openQuery
    • CADORecordset::openTable
    • CADORecordset::openStoredProc

Return Value

Returns TRUE if it was executed successfully.

See Sample

CADORecordset::Execute

The Execute function opens a recordset.

BOOL Execute(CADOCommand* pCommand);
throw(CADOException);

Parameters

CADOCommand* pCommand - A CADOCommand pointer.

Return Value

Returns TRUE if it was executed successfully.

See Sample

CADORecordset::GetQuery;

GetQuery returns the string containing the SQL SELECT statement.

CString GetQuery();

CADORecordset::SetQuery

void SetQuery(LPCSTR strQuery);

Parameters

LPCTSTR strQuery - A string pointer containing an SQL SELECT statement.

CADORecordset::RecordBinding

BOOL RecordBinding(CADORecordBinding pAdoRecordBinding);

Parameters

CADORecordBinding pAdoRecordBinding

CADORecordset::GetRecordCount

GetRecordCount returns the number of records accessed in the recordset.

DWORD GetRecordCount();

See Sample

CADORecordset::IsOpen

IsOpen determines if the recordset is open.

BOOL IsOpen();

Return Value

This member function returns TRUE if the recordset has not been closed.

CADORecordset::Close

The Close function closes the recordset.

void Close();

See Sample

CADORecordset::GetFieldCount

The GetFieldCount function returns the number of fields in the recordset.

long GetFieldCount();

CADORecordset::GetFieldValue

The GetFieldValue function returns a value that contains the value of a field.

BOOL GetFieldValue(LPCTSTR lpFieldName, int nValue);
BOOL GetFieldValue(int nIndex, int nValue);
BOOL GetFieldValue(LPCTSTR lpFieldName, long lValue);
BOOL GetFieldValue(int nIndex, long lValue);
BOOL GetFieldValue(LPCTSTR lpFieldName, unsigned long ulValue);
BOOL GetFieldValue(int nIndex, unsigned long ulValue);
BOOL GetFieldValue(LPCTSTR lpFieldName, double dbValue);
BOOL GetFieldValue(int nIndex, double dbValue);
BOOL GetFieldValue(LPCTSTR lpFieldName, CString strValue, 
                         CString strDateFormat = _T(""));
BOOL GetFieldValue(int nIndex, CString strValue, 
                         CString strDateFormat = _T(""));
BOOL GetFieldValue(LPCTSTR lpFieldName, COleDateTime time);
BOOL GetFieldValue(int nIndex, COleDateTime time);
BOOL GetFieldValue(LPCTSTR lpFieldName, bool bValue);
BOOL GetFieldValue(int nIndex, bool bValue);
BOOL GetFieldValue(LPCTSTR lpFieldName, COleCurrency cyValue);
BOOL GetFieldValue(int nIndex, COleCurrency cyValue);
throw(CADOException);

Parameters

  • LPCTSTR lpFieldName - A pointer to a string that contains the name of a field.
  • int nIndex - A zero-based index of the field in the recordset’s Fields collection, for lookup by index.
  • double dbValue - A reference to an object that will store the value of a field.
  • long lValue - A reference to an object that will store the value of a field.
  • unsigned long ulValue - A reference to an object that will store the value of a field.
  • int nValue - A reference to an object that will store the value of a field.
  • CString strValue - A reference to an object that will store the value of a field.
  • CString strDateFormat - A formatting time string similar to the strftime formatting string. The more common are:
    • %a - Abbreviated weekday name
    • %A - Full weekday name
    • %b - Abbreviated month name
    • %B - Full month name
    • %c - Date and time representation appropriate for locale
    • %d - Day of month as decimal number (01 - 31)
    • %H - Hour in 24-hour format (00 - 23)
    • %I - Hour in 12-hour format (01 - 12)
    • %j - Day of year as decimal number (001 - 366)
    • %m - Month as decimal number (01 - 12)
    • %M - Minute as decimal number (00 - 59)
    • %p - Current locale’s A.M./P.M. indicator for 12-hour clock
    • %S - Second as decimal number (00 - 59)
    • %U - Week of year as decimal number, with Sunday as first day of week (00 - 53)
    • %w - Weekday as decimal number (0 - 6; Sunday is 0)
    • %W - Week of year as decimal number, with Monday as first day of week (00 - 53)
    • %x - Date representation for current locale
    • %X - Time representation for current locale
    • %y - Year without century, as decimal number (00 - 99)
    • %Y - Year with century, as decimal number
  • COleDateTime time - A reference to an object that will store the value of a field.
  • bool bValue - A reference to an object that will store the value of a field.
  • COleCurrency cyValue - A reference to an object that will store the value of a field.

See Sample

CADORecordset::IsFieldNull

The IsFieldNull function determines if the field data is null.

BOOL IsFieldNull(LPCTSTR lpFieldName);
BOOL IsFieldNull(int nIndex);
throw(CADOException);

Parameters

  • LPCTSTR lpFieldName - A pointer to a string that contains the name of a field.
  • int nIndex - A zero-based index of the field in the recordset’s Fields collection, for lookup by index.

Return Value

This function returns TRUE if the field data is null.

CADORecordset::IsFieldEmpty

The IsFieldEmpty function determines if the field data is empty.

BOOL IsFieldEmpty(LPCTSTR lpFieldName);
BOOL IsFieldEmpty(int nIndex);
throw(CADOException);

Parameters

  • LPCTSTR lpFieldName - A pointer to a string that contains the name of a field.
  • int nIndex - A zero-based index of the field in the recordset’s Fields collection, for lookup by index.

Return Value

This function returns TRUE if the field data is empty.

CADORecordset::IsEof

BOOL IsEof();

Return Value

This function returns TRUE if the current position contains no records.

See Sample

CADORecordset::IsBof

BOOL IsBof();

Return Value

This function returns TRUE if the current position is the bottom of the recordset.

CADORecordset::MoveFirst
CADORecordset::MoveNext
CADORecordset::MovePrevious
CADORecordset::MoveLast

These functions make the first/next/previous/or last record of the recordset as the current record.

void MoveFirst();
void MoveNext();
void MovePrevious();
void MoveLast();

See Sample

CADORecordset::GetAbsolutePage
CADORecordset::SetAbsolutePage

Indicates on which page the current record resides.

long GetAbsolutePage();
void SetAbsolutePage(int nPage);

Parameters

int nPage - The number of the page starting from 1.

See Sample

CADORecordset::GetPageCount

GetPageCount returns the number of pages in the recordset.

long GetPageCount();

See Sample

CADORecordset::GetPageSize
CADORecordset::SetPageSize

Indicates the number of records per page.

long GetPageSize();
void SetPageSize(int nSize);

Parameters

int nSize - set the number of records per page.

For example

CADORecordset* pRs = new CADORecordset(pDb);

if(pRs->Open("MyBigTable", CADORecordset::openTable))
{
    pRs->SetPageSize(5);
    for(register int nPageIndex = 1; nPageIndex <= pRs->GetPageCount(); 
        nPageIndex++)
    {
        pRs->SetAbsolutePage(nPageIndex);
        for(register int nRecNumber = 0; nRecNumber < pRs->GetPageSize(); 
            nRecNumber++)
        {
            long lVal;
            pRs->GetFieldValue("ID", lVal);
            pRs->MoveNext();

            if(pRs->IsEof())
                break;
        }
    }
    pRs->Close();
}

delete pRs;

CADORecordset::GetAbsolutePosition
CADORecordset::SetAbsolutePosition

Indicates the position of the record in the recordset.

long GetAbsolutePosition();
void SetAbsolutePosition(int nPosition);

Parameters

int nPosition - Move to the position in the recordset.

GetAbsolutePosition() can return the position of the record or one of the following values:

  • CADORecordset::positionUnknown
  • CADORecordset::positionBOF
  • CADORecordset::positionEOF

CADORecordset::GetFieldInfo

GetFieldInfo returns the attributes of a field.

BOOL GetFieldInfo(LPCTSTR lpFieldName, CAdoFieldInfo* fldInfo);
BOOL GetFieldInfo(int nIndex, CAdoFieldInfo* fldInfo);

Parameters

  • LPCTSTR lpFieldName - A pointer to a string that contains the name of a field.
  • int nIndex - A zero-based index of the field in the recordset's Fields collection, for lookup by index.
  • CAdoFieldInfo* fldInfo - A struct that returns the field attributes. 
struct CADOFieldInfo
{
    char m_strName[30];
    short m_nType;
    long m_lSize;
    long m_lDefinedSize;
    long m_lAttributes;
    short m_nOrdinalPosition;
    BOOL m_bRequired;
    BOOL m_bAllowZeroLength;
    long m_lCollatingOrder;
};

The element m_nType of the class CADOFieldInfo can be one of the following values:

  • CADORecordset::typeEmpty
  • CADORecordset::typeTinyInt
  • CADORecordset::typeSmallInt
  • CADORecordset::typeInteger
  • CADORecordset::typeBigInt
  • CADORecordset::typeUnsignedTinyInt
  • CADORecordset::typeUnsignedSmallInt
  • CADORecordset::typeUnsignedInt
  • CADORecordset::typeUnsignedBigInt
  • CADORecordset::typeSingle
  • CADORecordset::typeDouble
  • CADORecordset::typeCurrency
  • CADORecordset::typeDecimal
  • CADORecordset::typeNumeric
  • CADORecordset::typeBoolean
  • CADORecordset::typeError
  • CADORecordset::typeUserDefined
  • CADORecordset::typeVariant
  • CADORecordset::typeIDispatch
  • CADORecordset::typeIUnknown
  • CADORecordset::typeGUID
  • CADORecordset::typeDate
  • CADORecordset::typeDBDate
  • CADORecordset::typeDBTime
  • CADORecordset::typeDBTimeStamp
  • CADORecordset::typeBSTR
  • CADORecordset::typeChar
  • CADORecordset::typeVarChar
  • CADORecordset::typeLongVarChar
  • CADORecordset::typeWChar
  • CADORecordset::typeVarWChar
  • CADORecordset::typeLongVarWChar
  • CADORecordset::typeBinary
  • CADORecordset::typeVarBinary
  • CADORecordset::typeLongVarBinary
  • CADORecordset::typeChapter
  • CADORecordset::typeFileTime
  • CADORecordset::typePropVariant
  • CADORecordset::typeVarNumeric
  • CADORecordset::typeArray

For example

if(prs->Open("Clients", CADORecordset::openTable))
{
    CADOFieldInfo pInfo;

    prs->GetFieldInfo("Description", &pInfo);

    if(pInfo.m_nType == CADORecordset::typeVarChar)
        AfxMessageBox("The type Description Field Is VarChar");
}


if(prs->Open("TestTable", CADORecordset::openTable))
{
    CADOFieldInfo* fInfo = new CADOFieldInfo;

    prs.GetFieldInfo(0, fInfo);
    CString strFieldName = fInfo->m_strName;
    prs->Close();
}

Return Value

Returns TRUE if it was executed successfully.

CADORecordset::GetChunk

This function returns all, or a portion, of the contents of a large text or binary data Field object.

BOOL GetChunk(LPCTSTR lpFieldName, CString& strValue);
BOOL GetChunk(int nIndex, CString& strValue);
BOOL GetChunk(LPCTSTR lpFieldName, LPVOID pData);
BOOL GetChunk(int nIndex, LPVOID pData);

Parameters

  • LPCTSTR lpFieldName - A pointer to a string that contains the name of a field.
  • int nIndex - A zero-based index of the field in the recordset's Fields collection, for lookup by index.
  • CString& strValue - A string pointer that contains the data that returns from the object.
  • LPVOID pData - A pointer that contains the data that returns from the object.

Return Value

Returns TRUE if it was executd successfully.

See Sample

CADORecordset::AppendChunk

This function appends data to a large text or binary data field.

BOOL AppendChunk(LPCTSTR lpFieldName, LPVOID lpData, UINT nBytes);
BOOL AppendChunk(int nIndex, LPVOID lpData, UINT nBytes);
throw(CADOException);

Parameters

  • LPCTSTR lpFieldName - A pointer to a string that contains the name of a field.
  • int nIndex - A zero-based index of the field in the recordset's Fields collection, for lookup by index.
  • LPVOID lpData - A pointer that contains the data to append to the object.
  • UINT nBytes - A UINT that indicates the size of the data to be inserted.

Return Value

Returns TRUE if it was executed successfully.

For example

//Sample of AppendChunck

prs.AddNew();
prs.SetFieldValue("ID", 5);
prs.SetFieldValue("Description", "Client 05");
prs.SetFieldValue("Checker", 1);
prs.AppendChunk("Document", 
    "This Document is the story of Bob and his Friends...", 37);
prs.Update();

//Sample of GetChunck

char data[1024];
prs.GetChunk("Document", (LPVOID)&data);

CADORecordset::GetString

This function returns a recordset as a string.

CString GetString(LPCTSTR lpCols, LPCTSTR lpRows, LPCTSTR lpNull, 
                  long numRows = 0);

Parameters

  • LPCTSTR lpCols - A columns delimiter.
  • LPCTSTR lpRows - A rows delimiter.
  • LPCTSTR lpNull - An expression that represents a null value.
  • long numRows - The number of rows affected.

CADORecordset::GetLastError

The GetLastError function returns the last error code.

DWORD GetLastError();

CADORecordset::GetLastErrorString

The GetLastErrorString function returns the last error string.

CString GetLastErrorString();

CADORecordset::AddNew

The AddNew function adds a record in the open recordset.

BOOL AddNew();
throw(CADOException);

Return Value

Returns TRUE if it was executed successfully.

See Sample

CADORecordset::Edit

The Edit function allows changes to the current record in the open recordset.

void Edit();

CADORecordset::Delete

The Delete function deletes the current record in the open recordset.

BOOL Delete();

Return Value

Returns TRUE if it was executed successfully.

CADORecordset::Update

The Update function updates the pending updates in the current record.

BOOL Update();
throw(CADOException);

Return Value

Returns TRUE if it was executed successfully.

See Sample

CADORecordset::CancelUpdate

The CancelUpdate function cancels any pending update in the open recordset.

void CancelUpdate();

CADORecordset::SetFieldValue

The SetFieldValue function sets the value of a field.

BOOL SetFieldValue(int nIndex, int nValue);
BOOL SetFieldValue(LPCTSTR lpFieldName, int nValue);
BOOL SetFieldValue(int nIndex, long lValue);
BOOL SetFieldValue(LPCTSTR lpFieldName, long lValue);
BOOL SetFieldValue(int nIndex, unsigned long ulValue);
BOOL SetFieldValue(LPCTSTR lpFieldName, unsigned long ulValue);
BOOL SetFieldValue(int nIndex, double dblValue);
BOOL SetFieldValue(LPCTSTR lpFieldName, double dblValue);
BOOL SetFieldValue(int nIndex, CString strValue);
BOOL SetFieldValue(LPCTSTR lpFieldName, CString strValue);
BOOL SetFieldValue(int nIndex, COleDateTime time);
BOOL SetFieldValue(LPCTSTR lpFieldName, COleDateTime time);
BOOL SetFieldValue(int nIndex, bool bValue);
BOOL SetFieldValue(LPCTSTR lpFieldName, bool bValue);
BOOL SetFieldValue(int nIndex, COleCurrency cyValue);
BOOL SetFieldValue(LPCTSTR lpFieldName, COleCurrency cyValue);

Parameters

  • LPCTSTR lpFieldName - A pointer to a string that contains the name of a field.
  • int nIndex - A zero-based index of the field in the recordset’s Fields collection, for lookup by index.
  • int nValue - A pointer to an object containing the value of the field.
  • long lValue - A pointer to an object containing the value of the field.
  • unsigned long lValue - A pointer to an object containing the value of the field.
  • double dbValue - A pointer to an object containing the value of the field.
  • CString strValue - A pointer to an object containing the value of the field.
  • COleDateTime time - A pointer to an object containing the value of the field.
  • bool bValue - A pointer to an object containing the value of the field.
  • COleCurrency cyValue - A pointer to an object containing the value of the field.

Return Value

Returns TRUE if it was executed successfully.

See Sample

For example

CADORecordset* prs = new CADORecordset(m_pAdoDb);
prs->Open("Test", openTable);

prs->AddNew();
prs->SetFieldValue(0, "dataU");
prs->SetFieldValue(1, "data01");
prs->SetFieldValue(2, (long)51000);
COleDateTime time = COleDateTime(2001,6,15, 10, 8, 30);
prs->SetFieldValue(3, time);
prs->Update();
prs->Close();

delete prs;

CADORecordset::Find

The Find function locates a string from the current position in the open recordset using an operator of comparison.

BOOL Find(LPCTSTR lpFind, 
          int nSearchDirection = CADORecordset::searchForward);

Parameters

  • LPCTSTR lpFind - A string expression used to locate the record.
  • int nSearchDirection - A value that indicates the type of operation. The possible values are:
    • CADORecordset::searchForward - Find the next location.
    • CADORecordset::searchBackward - Find the previous location.

Return Value

Returns TRUE if it was executed successfully.

For example

if(prs.Find("Field0 LIKE 'dataU%'"))
{
  prs.Delete();
  while(prs.FindNext())
    prs.Delete();
}

CADORecordset::FindFirst

The FindFirst function locates a string from the beginning in the open recordset using an operator of comparison.

BOOL FindFirst(LPCTSTR lpFind);

Parameters

LPCTSTR lpFind - A string expression used to locate the record.

Return Value

Returns TRUE if it was executed successfully.

CADORecordset::FindNext

The FindNext function locates a string from the last position in the open recordset using the operator of comparison used in FindFirst or Find functions.

BOOL FindNext();

Return Value

Returns TRUE if it was executed successfully.

See Sample

CADORecordset::GetBookmark

The GetBookmark function saves the position of the current record.

BOOL GetBookmark();

Return Value

Returns TRUE if it was executed successfully.

CADORecordset::SetBookmark

The SetBookmark function returns to the position saved at any time.

void SetBookmark();

Return Value

Returns TRUE if it was executed successfully.

CADORecordset::SetFilter

The SetFilter indicates a filter for data in an open Recordset.

BOOL SetFilter(LPCTSTR strFilter);
throw(CADOException);

Parameters

LPCTSTR strFilter - a string composed by one or more individual clauses concatenated with AND or OR operators.

Return Value

Returns TRUE if it was executed successfully.

For example

CADORecordset* pRs = new CADORecordset(pDb);

if(pRs->Open("tblTest", CADORecordset::openTable))
{
    CString strFilter = _T("LastName = 'Smith' And Age > 30");
    pRs->SetFilter(strFilter);
    .
    .
    pRs->Close();
}

delete pRs

CADORecordset::SetSort

The SetSort function sets the sort order for records in a CADORecordset object.

BOOL SetSort(LPCTSTR lpstrCriteria);
throw(CADOException);

Parameters

LPCTSTR lpstrCriteria - A string that contains the ORDER BY clause of an SQL statement.

Return Value

Returns TRUE if it was executed successfully.

CADORecordset::GetRecordset

The GetRecordset function returns a pointer to an open recordset.

_RecordsetPtr GetRecordset();

CADORecordset::GetActiveConnection

The GetActiveConnection returns the active connection.

_ConnectionPtr GetActiveConnection();

CADORecordset::Clone

The Clone function creates a duplicate CADORecordset object from an existing CADORecordset object.

BOOL Clone(CADORecordset pAdoRecordset);
throw(CADOException);

Parameters

CADORecordset pAdoRecordset is an existing CADORecordset object.

Return Value

Returns TRUE if it was executed successfully.

For example

CADORecordset m_pRs; //Original Recordset

CADORecordset RS;   //Duplicate Recordset

CADORecordset* pRs = CADORecordset(m_pDb);

if(pRs->Open("tblTest", CADORecordset::openTable)) //Open the Original 

Recordset
{
    pRs->Clone(RS); //Create the clone of the original Recordset


    long lClonRecs = RS.GetRecordCount();
    long lOrigRecs = m_pRs->GetRecordCount();
    .
    .
    RS.Close();
    pRs->Close();
}

delete pRs;

CADORecordset::SaveAsXML

The SaveAsXML function saves the open recordset in a file with XML format.

BOOL SaveAsXML(LPCTSTR lpstrXMLFile);

Parameters

LPCTSTR strXMLFile - a string that indicates the complete path name of the file where the recordset is to be saved.

Return Value

Returns TRUE if it was executed successfully.

CADORecordset::OpenXML

The OpenXML function opens a XML file format in a recordset.

BOOL OpenXML(LPCTSTR lpstrXMLFile);

Parameters

LPCTSTR strXMLFile - a string that indicates the complete path name of the XML file to be opened.

Return Value

Returns TRUE if it was executed successfully.

For example

CADORecordset* pRs = CADORecordset(pDB);

if(prs->OpenXML("C:\\My.XML"))
{
    CString strClient = _T("");
    double dblVal = 0;
    long lrecs = prs->GetRecordCount();

    if(!prs->IsEof())
        prs->MoveFirst();

    prs->GetFieldValue("Budget", dblVal);
    prs->GetFieldValue("ClientName", strClient);

    prs->Close();
}

CADORecordset::OpenSchema

The OpenSchema function obtains database schema information from the provider.

BOOL OpenSchema(int nSchema, LPCTSTR SchemaID = _T(""));
throw(CADOException);

Parameters

  • int nSchema - A value that represents the type of schema query.
  • LPCTSTR SchemaID = _T("") - The GUID for a provider-schema query not defined by the OLE DB specification.
Constant Value Description Constraint Columns
schemaAsserts 0 Returns the assertions defined in the catalog that are owned by a given user.

(ASSERTIONS Rowset)

 CONSTRAINT_ CATALOG*
CONSTRAINT_ SCHEMA*
CONSTRAINT_NAME
schemaCatalogs 1 Returns the physical attributes associated with catalogs accessible from the DBMS.

(CATALOGS Rowset)

 CATALOG_NAME
schemaCharacterSets 2 Returns the character sets defined in the catalog that are accessible to a given user.

(CHARACTER_SETS Rowset)

 CHARACTER_ SET_CATALOG*
CHARACTER_ SET_SCHEMA*
CHARACTER_SET _NAME*
schemaCheckConstraints 5 Returns the check constraints defined in the catalog that are owned by a given user.

(CHECK_CONSTRAINTS Rowset)

 CONSTRAINT_ CATALOG*
CONSTRAINT_ SCHEMA*
CONSTRAINT_NAME
schemaCollations 3

Returns the character collations defined in the catalog that are accessible to a given user.

(COLLATIONS Rowset)

 COLLATION_ CATALOG*
COLLATION_SCHEMA
COLLATION_NAME
schemaColumnPrivileges 13

Returns the privileges on columns of tables defined in the catalog that are available to, or granted by, a given user.

(COLUMN_PRIVILEGES Rowset)

 TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
COLUMN_NAME
GRANTOR
GRANTEE
schemaColumns 4

Returns the columns of tables (including views) defined in the catalog that are accessible to a given user.

(COLUMNS Rowset)

 TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
COLUMN_NAME
schemaColumnsDomainUsage 11 Returns the columns defined in the catalog that are dependent on a domain defined in the catalog and owned by a given user.

(COLUMN_DOMAIN_USAGE Rowset)

 DOMAIN_CATALOG
DOMAIN_SCHEMA
DOMAIN_NAME
COLUMN_NAME
schemaConstraintColumnUsage 6 Returns the columns used by referential constraints, unique constraints, check constraints, and assertions, defined in the catalog and owned by a given user.

(CONSTRAINT_COLUMN_USAGE Rowset)

 TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
COLUMN_NAME
schemaConstraintTableUsage 7 Returns the tables that are used by referential constraints, unique constraints, check constraints, and assertions defined in the catalog and owned by a given user.

(CONSTRAINT_TABLE_USAGE Rowset)

 TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
schemaCubes 32 Returns information about the available cubes in a schema (or the catalog, if the provider does not support schemas).

(CUBES Rowset*)

 CATALOG_NAME
SCHEMA_NAME
CUBE_NAME
schemaDBInfoKeywords 30 Returns a list of provider-specific keywords.

(IDBInfo::GetKeywords*)

 <None>
schemaDBInfoLiterals 31 Returns a list of provider-specific literals used in text commands.

(IDBInfo::GetLiteralInfo*)

 <None>
schemaDimensions 33 Returns information about the dimensions in a given cube. It has one row for each dimension.

(DIMENSIONS Rowset*)

 CATALOG_NAME
SCHEMA_NAME
CUBE_NAME
DIMENSION_NAME
DIMENSION_ UNIQUE_NAME*
schemaForeignKeys 27 Returns the foreign key columns defined in the catalog by a given user.

(FOREIGN_KEYS Rowset)

 PK_TABLE_CATALOG
PK_TABLE_SCHEMA
PK_TABLE_NAME
FK_TABLE_CATALOG
FK_TABLE_SCHEMA
FK_TABLE_NAME
schemaHierarchies 34 Returns information about the hierarchies available in a dimension.

(HIERARCHIES Rowset*)

 CATALOG_NAME
SCHEMA_NAME
CUBE_NAME
DIMENSION_ UNIQUE_NAME*
HIERARCHY_NAME
HIERARCHY_ UNIQUE_NAME*
schemaIndexes 12 Returns the indexes defined in the catalog that are owned by a given user.

(INDEXES Rowset)

 TABLE_CATALOG
TABLE_SCHEMA
INDEX_NAME
TYPE
TABLE_NAME
schemaKeyColumnUsage 8 Returns the columns defined in the catalog that are constrained as keys by a given user.

(KEY_COLUMN_USAGE Rowset)

 CONSTRAINT_ CATALOG*
CONSTRAINT_ SCHEMA*
CONSTRAINT_NAME
TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
COLUMN_NAME
schemaLevels 35 Returns information about the levels available in a dimension.

(LEVELS Rowset*)

 CATALOG_NAME
SCHEMA_NAME
CUBE_NAME
DIMENSION_ UNIQUE_NAME*
HIERARCHY_ UNIQUE_NAME*
LEVEL_NAME
LEVEL_ UNIQUE_NAME*
schemaMeasures 36 Returns information about the available measures.

(MEASURES Rowset*)

 CATALOG_NAME
SCHEMA_NAME
CUBE_NAME
MEASURE_NAME
MEASURE_ UNIQUE_NAME*
schemaMembers 38 Returns information about the available members.

(MEMBERS Rowset*)

 CATALOG_NAME
SCHEMA_NAME
CUBE_NAME
DIMENSION_ UNIQUE_NAME*
HIERARCHY_ UNIQUE_NAME*
LEVEL_ UNIQUE_NAME*
LEVEL_NUMBER
MEMBER_NAME
MEMBER_UNIQUE _NAME*
MEMBER_CAPTION
MEMBER_TYPE
Tree operator (For more information, see the OLE DB for OLAP documentation.)
schemaPrimaryKeys 28 Returns the primary key columns defined in the catalog by a given user.

(PRIMARY_KEYS Rowset)

 PK_TABLE_CATALOG
PK_TABLE_SCHEMA
PK_TABLE_NAME
schemaProcedureColumns 29 Returns information about the columns of rowsets returned by procedures.

(PROCEDURE_COLUMNS Rowset)

 PROCEDURE_ CATALOG*
PROCEDURE_SCHEMA
PROCEDURE_NAME
COLUMN_NAME
schemaProcedureParameters 26 Returns information about the parameters and return codes of procedures.

(PROCEDURE_PARAMETERS Rowset)

 PROCEDURE_ CATALOG*
PROCEDURE_SCHEMA
PROCEDURE_NAME
PARAMETER_NAME
schemaProcedures 16 Returns the procedures defined in the catalog that are owned by a given user.

(PROCEDURES Rowset)

 PROCEDURE_ CATALOG*
PROCEDURE_SCHEMA
PROCEDURE_NAME
PROCEDURE_TYPE
schemaProperties 37 Returns information about the available properties for each level of the dimension.

(PROPERTIES Rowset*)

 CATALOG_NAME
SCHEMA_NAME
CUBE_NAME
DIMENSION_ UNIQUE_NAME*
HIERARCHY_ UNIQUE_NAME*
LEVEL_ UNIQUE_NAME*
MEMBER_ UNIQUE_NAME*
PROPERTY_TYPE
PROPERTY_NAME
schemaProviderSpecific -1 Used if the provider defines its own nonstandard schema queries. <Provider specific>
schemaProviderTypes 22 Returns the (base) data types supported by the data provider.

(PROVIDER_TYPES Rowset)

 DATA_TYPE
BEST_MATCH
schemaReferentialConstraints 9 Returns the referential constraints defined in the catalog that are owned by a given user.

(REFERENTIAL_CONSTRAINTS Rowset)

 CONSTRAINT_ CATALOG*
CONSTRAINT_ SCHEMA*
CONSTRAINT_NAME
schemaSchemata 17 Returns the schemas (database objects) that are owned by a given user.

(SCHEMATA Rowset)

 CATALOG_NAME
SCHEMA_NAME
SCHEMA_OWNER
schemaSQLLanguages 18 Returns the conformance levels, options, and dialects supported by the SQL-implementation processing data defined in the catalog.

(SQL_LANGUAGES Rowset)

 <None>
schemaStatistics 19 Returns the statistics defined in the catalog that are owned by a given user.

(STATISTICS Rowset)

 TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
schemaTableConstraints 10 Returns the table constraints defined in the catalog that are owned by a given user.

(TABLE_CONSTRAINTS Rowset)

 CONSTRAINT_ CATALOG*
CONSTRAINT_ SCHEMA*
CONSTRAINT_NAME
TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
CONSTRAINT_TYPE
schemaTablePrivileges 14 Returns the privileges on tables defined in the catalog that are available to, or granted by, a given user.

(TABLE_PRIVILEGES Rowset)

 TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
GRANTOR
GRANTEE
schemaTables 20 Returns the tables (including views) defined in the catalog that are accessible to a given user.

(TABLES Rowset)

 TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
TABLE_TYPE
schemaTranslations 21 Returns the character translations defined in the catalog that are accessible to a given user.

(TRANSLATIONS Rowset)

 TRANSLATION_ CATALOG*
TRANSLATION_ SCHEMA*
TRANSLATION _NAME*
schemaTrustees 39 Reserved for future use.  
schemaUsagePrivileges 15 Returns the USAGE privileges on objects defined in the catalog that are available to, or granted by, a given user.

(USAGE_PRIVILEGES Rowset)

 OBJECT_CATALOG
OBJECT_SCHEMA
OBJECT_NAME
OBJECT_TYPE
GRANTOR
GRANTEE
schemaViewColumnUsage 24 Returns the columns on which viewed tables, defined in the catalog and owned by a given user, are dependent.

(VIEW_COLUMN_USAGE Rowset)

 VIEW_CATALOG
VIEW_SCHEMA
VIEW_NAME
schemaViews 23 Returns the views defined in the catalog that are accessible to a given user.

(VIEWS Rowset)

 TABLE_CATALOG
TABLE_SCHEMA
TABLE_NAME
schemaViewTableUsage 25 Returns the tables on which viewed tables, defined in the catalog and owned by a given user, are dependent.

(VIEW_TABLE_USAGE Rowset)

 VIEW_CATALOG
VIEW_SCHEMA
VIEW_NAME

* Ignore the spaces in these values, as they have been added to avoid page scrolling.

Return Value

Returns TRUE if it was executed successfully.

For Example

try
{
    CAD if(pdb.Open("Data Source=sysdevpdc;Provider=" 
                    "MSOLAP;Initial Catalog=Foodmart 2000"))
    {
        CADORecordset prs(&pdb);
        if(prs.OpenSchema(CADORecordset::schemaMeasures))
        {
            while(!prs.IsEof())
            {dset::schemaMeasures))
        {
            while(!prs.IsEof())
            {
                CString strValue;
                CString strUniqueName;
                CString strSqlColumnName;
                int nDataType = 0;
                int nValue = 0;

                prs.GetFieldValue("CUBE_NAME", strValue);
                prs.GetFieldValue("MEASURE_NAME", strValue);
                prs.GetFieldValue("MEASURE_AGGREGATOR", nValue);
                prs.GetFieldValue("MEASURE_UNIQUE_NAME", 
                                                  strUniqueName);
                prs.GetFieldValue("MEASURE_NAME_SQL_COLUMN_NAME", 
                                               strSqlColumnName);
                prs.GetFieldValue("DATA_TYPE", nDataType);
                prs.MoveNext();
            }
        }
        prs.Close();
    }
}
catch(CADOException &e)
{
...
}

CADORecordset::Requery

The Requery function refreshes an open recordset.

BOOL Requery();
throw(CADOException);

Return Value

Returns TRUE if it was executed successfully.

Sample 01:

CADODatabase* pAdoDb = new CADODatabase();
CString strConnection = "";

strConnection = _T("Provider=MSDASQL;"
                  "PersistSecurityInfo=False;Trusted_Connection=Yes
Data Source=Access Sql Server;catalog=sampledb");

if(pAdoDb->Open((LPCTSTR)strConnection))
{
    CString strQry = _T("");
    int numRecords;

    strQry.Format(_T("sp_StoreClientFields_ps '%s', %d"), 
                  (LPCTSTR)strParam1, nParam2);

    CADORecordset* pRs = new CADORecordset(pAdoDb);

    if(!pRs->Open((LPCTSTR)strQry))
    {
    delete pRs;
    delete pAdoDb;
    return FALSE
    }

    numRecords = pRs->GetRecordCount();
    while(!pRs->IsEof())
    {
      CString strVal = _T("");
      int nVal = 0;
      //Get Numeric Field Value

      pRs->GetFieldValue("NumField1", nVal)

      //Get String Field Data

      pRs->GetFieldValue("StrField..", strVal)
        DoSomething(nVal, strVal);

        pRs->MoveNext();
    }
    pRs->Close();
}
else
  return FALSE;

The CADOParameter Class

The CADOParameter class has a set of functions that corresponds to the _ParameterPtr.

CADOParameter::CADOParameter

Creates a CADOParameter object.

CADOParameter(int nType, long lSize = 0, int nDirection = paramInput, 
              CString strName = _T(""));

Parameters

  • int nType - An int value that specifies the data type of the CADOParameter object. Can be one of the values specified in CADORecordset::GetFieldInfo. If you are using CADORecordset::typeNumeric or CADORecordset::typeDecimal, you must define the precision and scale values.
  • long lSize = 0 - An optional long value that specifies the maximum length for the parameter value in bytes or characters.
  • int nDirection = paramInput - An optional int value that specifies the direction of the CADOParameter object. Can be one of the following values:
    • CADOParameter::paramUnknown - Indicates that the parameter direction is unknown.
    • CADOParameter::paramInput - Default. Indicates that the parameter represents an input parameter.
    • CADOParameter::paramOutput - Indicates that the parameter represents an output parameter.
    • CADOParameter::paramInputOutput - Indicates that the parameter represents both an input and output parameter.
    • CADOParameter::paramReturnValue - Indicates that the parameter represents a return value.
    • CString strName = _T("") - An optional string that specifies the name of the CADOParameter object.

See Sample

CADOParameter::SetValue

The SetValue function sets the value for the CADOParameter object.

BOOL SetValue(int nValue);
BOOL SetValue(long lValue);
BOOL SetValue(double dbValue);
BOOL SetValue(CString strValue);
BOOL SetValue(COleDateTime time);
BOOL SetValue(_variant_t vtValue);

Parameters

  • int nValue - An int value containing the parameter value.
  • long lValue - A long value containing the parameter value.
  • double dbValue - A double value containing the parameter value.
  • CString strValue - A string value containing the parameter value.
  • COleDateTime time - A time value containing the parameter value.
  • _variant_t vtValue - A variant value containing the parameter value.

Return Value

Returns TRUE if it was executed successfully.

See Sample

CADOParameter::SetPrecision

The SetPrecison function sets the precision for the CADOParameter object.

void SetPrecision(int nPrecision);

CADOParameter::SetScale

The SetScale function sets the scale for the CADOParameter object.

void SetScale(int nScale);

CADOParameter::GetValue

The GetValue function returns the value of the CADOParameter object.

BOOL GetValue(int& nValue);
BOOL GetValue(long& lValue);
BOOL GetValue(double& dbValue);
BOOL GetValue(CString& strValue, CString strDateFormat = _T(""));
BOOL GetValue(COleDateTime& time);
BOOL GetValue(_variant_t& vtValue);

Parameters

  • int& nValue - A reference to an int that will store the value of the parameter.
  • long& lValue - A reference to a long that will store the value of the parameter.
  • double& dbValue - A reference to a double that will store the value of the parameter.
  • CString& strValue - A reference to a string that will store the value of the parameter.
  • CString strDateFormat = _T("") - A formatting time string similar to the strftime formatting string.
  • COleDateTime& time - A reference to a time object that will store the value of the parameter.
  • _variant_t& vtValue - A reference to a variant object that will store the value of the parameter.

Return Value

Returns TRUE if it was executed successfully.

See Sample

CADOParameter::SetName

The SetName function sets the name of the CADOParameter object. 

CString SetName(CString strName);

Parameters

CString strName - A string specifying the parameter name.

CADOParameter::GetName

The GetName function returns the CADOParameter object.

CString GetName();

CADOParameter::GetType

The GetType function returns the type of the CADOParameter object.

int GetType();

CADOParameter::GetParameter

The GetParameter function returns a pointer to a _Parameter object.

_ParameterPtr GetParameter();

The CADOCommand Class

The CADOCommand class has a set of functions that corresponds to the _CommandPtr.

CADOCommand::CADOCommand

Creates a CADOCommand object.

CADOCommand(CADODatabase* pAdoDatabase, CString strCommandText = _T(""),
                                  int nCommandType = typeCmdStoredProc);

Parameters

  • CADODatabase* pAdoDatabase - A CADODatabase object pointer.
  • CString strCommandText = _T("") - An optional string that indicates the text of the CADOCcommand object.
  • int nCommandType = typeCmdStoredProc - An optional int value that indicates the type of the CADOCommand object. Can be one of the following values:
    • CADOCommand::typeCmdText - Evaluates CommandText as a textual definition of a command or stored procedure call.
    • CADOCommand::typeCmdTable - Evaluates CommandText as a table name whose columns are all returned by an internally generated SQL query.
    • CADOCommand::typeCmdTableDirect - Evaluates CommandText as a table name whose columns are all returned.
    • CADOCommand::typeCmdStoredProc - Default. Evaluates CommandText as a stored procedure name.
    • CADOCommand::typeCmdUnknown - Indicates that the type of the command in the CommandText property is not known.
    • CADOCommand::typeCmdFile - Evaluates CommandText as the file name of a persistently stored recordset. Used with Recordset.Open or Requery only.

See Sample

CADOCommand::AddParameter

The AddParameter function.

BOOL AddParameter(CADOParameter* pAdoParameter);
BOOL AddParameter(CString strName, int nType, int nDirection,
                          long lSize, int nValue);
BOOL AddParameter(CString strName, int nType, int nDirection,
                          long lSize, long lValue);
BOOL AddParameter(CString strName, int nType, int nDirection,
                          long lSize, double dblValue, int nPrecision = 0,
                          int nScale = 0);
BOOL AddParameter(CString strName, int nType, int nDirection,
                          long lSize, CString strValue);
BOOL AddParameter(CString strName, int nType, int nDirection,
                          long lSize, COleDateTime time);
BOOL AddParameter(CString strName, int nType, int nDirection,
                          long lSize, _variant_t vtValue, int nPrecision = 0,
                          int nScale = 0);

Parameters

  • CADOParameter* pAdoParameter - A pointer to a CADOParameter object.
  • CString strName - A string that specifies the name of the parameter.
  • int nType - An int value that specifies the data type of the CADOParameter object. Can be one of the values specified in CADORecordset::GetFieldInfo. If you are using CADORecordset::typeNumeric or CADORecordset::typeDecimal, you must define the precision and scale values.
  • int nDirection - An int value that specifies the direction of the CADOParameter object. Can be one of the values specified in CADOParameter::CADOParameter.
  • long lSize - A long value that specifies the maximum length for the parameter value in bytes or characters.
  • int nValue - An int value containing the parameter value.
  • long lValue - A long value containing the parameter value.
  • double dblValue - A double value containing the parameter value.
  • int nPrecision - An int value containing the precision of the parameter value.
  • int nScale - An int value containing the scale of the parameter value.
  • CString strValue - A string value containing the parameter value.
  • COleDateTime time - A time value containing the parameter value.
  • _variant_t vtValue - A variant value containing the parameter value.

Return Value

Returns TRUE if it was executed successfully.

See Sample

CADOCommand::SetText

The SetText function sets the command text of the CADOCommand object.

void SetText(CString strCommandText);

Parameters

CString strCommandText - A string that indicates the command text.

CADOCommand::GetText

The GetText function returns the command text of the CADOCommand object.

CString GetText();

CADOCommand::SetType

The SetType function sets the type of the CADOCommand object.

void SetType(int nCommandType);

Parameters

int nCommandType - A int value that indicates the type of the command.

CADOCommand::GetType

The GetType function returns the type of the CADOCommand object.

int GetType();

CADOCommand::GetCommand

The GetCommand function returns a Command pointer.

_CommandPtr GetCommand();

CADOCommand::Execute

The Execute function executes a command text.

BOOLExecute();

Return Value

Returns TRUE if it was executed successfully.

CADOCommand::GetRecordsAffected

The GetRecordsAffected function returns the number of records affected by the last command executed.

int GetRecordsAffected();

Sample 02:

//SQL SCRIPT...
Create Procedure sp_OutputTest
@IN1 int,
@OutInt int Output,
@OutChar varchar(20) Output
As   
    SELECT    
        @OutChar = 'Hello World'
    SELECT    
        @OutInt = 10 * @IN1
    return (90)
GO


//Visual C++ Code...

CADOParameter pParamRetVal(CADORecordset::typeInteger, sizeof(int),
                           CADOParameter::paramReturnValue);
CADOParameter pParamIn(CADORecordset::typeInteger, sizeof(int));
CADOParameter pParamOutInt(CADORecordset::typeInteger, sizeof(int),
                           CADOParameter::paramOutput);
CADOParameter pParamOutChar(CADORecordset::typeChar, sizeof(char) * 20,
                            CADOParameter::paramOutput);

pParamIn.SetValue(2);

CADOCommand pCmd(&pDb, "sp_OutputTest");

pCmd.AddParameter(&pParamRetVal);
pCmd.AddParameter(&pParamIn);
pCmd.AddParameter(&pParamOutInt);
pCmd.AddParameter(&pParamOutChar);

CADORecordset* prs = new CADORecordset(pDb);

if(pRs->Execute(&pCmd))
{
    int nVal = 0;
    int nRetVal = 0;
    CString str = _T("");

    pParamRetVal.GetValue(nRetVal);
    pParamOutInt.GetValue(nVal);
    pParamOutChar.GetValue(str);
}

delete pRS;

The CJectEngine Class

The CJetEngine class has a set of functions that corresponds to the _RecordsetPtr.

CJetEngine::CompactDatabase

Compacts an Access database.

BOOLCompactDatabase(CString strDatabaseSource, CString strDatabaseDestination)

Parameters

  • CString strDatabaseSource - A connection string to the source database.
  • CString strDatabaseDestination - A connection string to the destination database.

Remarks:

The connection strings must be like this: "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\the Database Path".

Return Value

Returns TRUE if it was executed successfully.

For example

CString strCompactedDBConnection;
CString strConnection;

CString strCompactedDBPath = _T("C:\\My Projects\\Database\\SampleDB.tmp");
CString strDatabasePath = _T("C:\\My Projects\\Database\\SampleDB.mdb");

strCompactedDBConnection.Format("Provider=Microsoft.Jet.OLEDB." 
        "4.0;Data Source=%s", strCompactedDBPath.GetBuffer(0));
strConnection.Format("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=%s", 
                                         strDatabasePath.GetBuffer(0));
if(CJetEngine::CCompactDatabase(strConnection, strCompactedDBConnection))
{
    ::CopyFile(strCompactedDBPath.GetBuffer(0), 
          strDatabasePath.GetBuffer(0), FALSE);
}

The CADOException Class

The CADOException class represents an exception condition. The class includes public data members you can use to determine the cause of the exception.

CADOException::CADOException

Creates a CADOException object.

CADOExcpetion();

To retrieve the ADO error information:

  • Construct a CADOException object.
  • Call any exception object’s GetErrorMesaage or GetError member function, to retrieve information about the error, via the exception object.

For Example

try
{
    if(pDb.Open(_T("Provider=Microsoft.JET.OLEDB.4.0;") 
                _T("Data source = c:\\vc projects\\ado\\dbTest.mdb;")))
    {
        CADORecordset pRS(&pDb);

        if(pRS.Open("tbltest", CADORecordset::openTable))
        {
            pRS.SetSort("Descriptions");
            .
            .
            .
        }
        pRS.Close();
    }
}
catch(CADOException &e)
{
    AfxMessageBox(e.GetErrorMessage());
}

CADOException::GetErrorMessage

CString GetErrorMessage() const;

Return Value

Returns error description.

S