分类目录归档:ADO & ADO.NET

ADO & ADO.NET

Type 属性范例 (Property) (VB)

Type 属性范例 (Property) (VB)

本范例演示 Type 属性。这是列出集合(如 Properties、Fields 等等)的名称和类型的实用程序模型。 继续阅读

GetRows 方法范例 (VB)

GetRows 方法范例 (VB)

本范例使用 GetRows 方法从 Recordset 中检索指定数目的行,并用结果数据填充一个数组。在两种情况下,GetRows 方法返回的行将少于所需的数目:一种情况是到达了 EOF,另一种情况是 GetRows 试图检索被其他用户删除的记录。仅在发生第二种情况时,该函数才返回 False。运行此过程需要 GetRowsOK 函数。 继续阅读

AddNew 方法范例 (VB)

AddNew 方法范例 (VB)本范例使用 AddNew 方法来创建具有指定名称的新记录。

'BeginAddNewVB

    'To integrate this code
    'replace the data source and initial catalog values
    'in the connection string

Public Sub Main()
    On Error GoTo ErrorHandler

    'recordset and connection variables
    Dim Cnxn As ADODB.Connection
    Dim rstEmployees As ADODB.Recordset
    Dim strCnxn As String
    Dim strSQL As String
     'record variables
    Dim strID As String
    Dim strFirstName As String
    Dim strLastName As String
    Dim blnRecordAdded As Boolean

    ' Open a connection
    Set Cnxn = New ADODB.Connection
    strCnxn = "Provider='sqloledb';Data Source='MySqlServer';" & _
        "Initial Catalog='Northwind';Integrated Security='SSPI';"
    Cnxn.Open strCnxn
       
    ' Open Employees Table with a cursor that allows updates
    Set rstEmployees = New ADODB.Recordset
    strSQL = "Employees"
    rstEmployees.Open strSQL, strCnxn, adOpenKeyset, adLockOptimistic, adCmdTable
    
    ' Get data from the user
    strFirstName = Trim(InputBox("Enter first name:"))
    strLastName = Trim(InputBox("Enter last name:"))
    
    ' Proceed only if the user actually entered something
    ' for both the first and last names
    If strFirstName <> "" And strLastName <> "" Then
    
        rstEmployees.AddNew
        rstEmployees!firstname = strFirstName
        rstEmployees!LastName = strLastName
        rstEmployees.Update
        blnRecordAdded = True
        
        ' Show the newly added data
        MsgBox "New record: " & rstEmployees!EmployeeId & " " & _
        rstEmployees!firstname & " " & rstEmployees!LastName
        
    Else
        MsgBox "Please enter a first name and last name."
    End If
          
    ' Delete the new record because this is a demonstration
    Cnxn.Execute "DELETE FROM Employees WHERE EmployeeID = '" & strID & "'"
     
    ' clean up
    rstEmployees.Close
    Cnxn.Close
    Set rstEmployees = Nothing
    Set Cnxn = Nothing
    Exit Sub
    
ErrorHandler:
   ' clean up
    If Not rstEmployees Is Nothing Then
        If rstEmployees.State = adStateOpen Then rstEmployees.Close
    End If
    Set rstEmployees = Nothing
    
    If Not Cnxn Is Nothing Then
        If Cnxn.State = adStateOpen Then Cnxn.Close
    End If
    Set Cnxn = Nothing
    
    If Err <> 0 Then
        MsgBox Err.Source & "-->" & Err.Description, , "Error"
    End If
End Sub
'EndAddNewVB

ADO 常量对照表

<%
'--------------------------------------------------------------------
' Microsoft ADO
'
' Copyright (c) 1996-1998 Microsoft Corporation.
'
'
'
' ADO constants include file for VBScript
'
'--------------------------------------------------------------------<!--more-->



'---- CursorTypeEnum Values ----
Const adOpenForwardOnly = 0
Const adOpenKeyset = 1
Const adOpenDynamic = 2
Const adOpenStatic = 3

'---- CursorOptionEnum Values ----
Const adHoldRecords = &H00000100
Const adMovePrevious = &H00000200
Const adAddNew = &H01000400
Const adDelete = &H01000800
Const adUpdate = &H01008000
Const adBookmark = &H00002000
Const adApproxPosition = &H00004000
Const adUpdateBatch = &H00010000
Const adResync = &H00020000
Const adNotify = &H00040000
Const adFind = &H00080000
Const adSeek = &H00400000
Const adIndex = &H00800000

'---- LockTypeEnum Values ----
Const adLockReadOnly = 1
Const adLockPessimistic = 2
Const adLockOptimistic = 3
Const adLockBatchOptimistic = 4

'---- ExecuteOptionEnum Values ----
Const adAsyncExecute = &H00000010
Const adAsyncFetch = &H00000020
Const adAsyncFetchNonBlocking = &H00000040
Const adExecuteNoRecords = &H00000080
Const adExecuteStream = &H00000400

'---- ConnectOptionEnum Values ----
Const adAsyncConnect = &H00000010

'---- ObjectStateEnum Values ----
Const adStateClosed = &H00000000
Const adStateOpen = &H00000001
Const adStateConnecting = &H00000002
Const adStateExecuting = &H00000004
Const adStateFetching = &H00000008

'---- CursorLocationEnum Values ----
Const adUseServer = 2
Const adUseClient = 3

'---- DataTypeEnum Values ----
Const adEmpty = 0
Const adTinyInt = 16
Const adSmallInt = 2
Const adInteger = 3
Const adBigInt = 20
Const adUnsignedTinyInt = 17
Const adUnsignedSmallInt = 18
Const adUnsignedInt = 19
Const adUnsignedBigInt = 21
Const adSingle = 4
Const adDouble = 5
Const adCurrency = 6
Const adDecimal = 14
Const adNumeric = 131
Const adBoolean = 11
Const adError = 10
Const adUserDefined = 132
Const adVariant = 12
Const adIDispatch = 9
Const adIUnknown = 13
Const adGUID = 72
Const adDate = 7
Const adDBDate = 133
Const adDBTime = 134
Const adDBTimeStamp = 135
Const adBSTR = 8
Const adChar = 129
Const adVarChar = 200
Const adLongVarChar = 201
Const adWChar = 130
Const adVarWChar = 202
Const adLongVarWChar = 203
Const adBinary = 128
Const adVarBinary = 204
Const adLongVarBinary = 205
Const adChapter = 136
Const adFileTime = 64
Const adPropVariant = 138
Const adVarNumeric = 139
Const adArray = &H2000

'---- FieldAttributeEnum Values ----
Const adFldMayDefer = &H00000002
Const adFldUpdatable = &H00000004
Const adFldUnknownUpdatable = &H00000008
Const adFldFixed = &H00000010
Const adFldIsNullable = &H00000020
Const adFldMayBeNull = &H00000040
Const adFldLong = &H00000080
Const adFldRowID = &H00000100
Const adFldRowVersion = &H00000200
Const adFldCacheDeferred = &H00001000
Const adFldIsChapter = &H00002000
Const adFldNegativeScale = &H00004000
Const adFldKeyColumn = &H00008000
Const adFldIsRowURL = &H00010000
Const adFldIsDefaultStream = &H00020000
Const adFldIsCollection = &H00040000

'---- EditModeEnum Values ----
Const adEditNone = &H0000
Const adEditInProgress = &H0001
Const adEditAdd = &H0002
Const adEditDelete = &H0004

'---- RecordStatusEnum Values ----
Const adRecOK = &H0000000
Const adRecNew = &H0000001
Const adRecModified = &H0000002
Const adRecDeleted = &H0000004
Const adRecUnmodified = &H0000008
Const adRecInvalid = &H0000010
Const adRecMultipleChanges = &H0000040
Const adRecPendingChanges = &H0000080
Const adRecCanceled = &H0000100
Const adRecCantRelease = &H0000400
Const adRecConcurrencyViolation = &H0000800
Const adRecIntegrityViolation = &H0001000
Const adRecMaxChangesExceeded = &H0002000
Const adRecObjectOpen = &H0004000
Const adRecOutOfMemory = &H0008000
Const adRecPermissionDenied = &H0010000
Const adRecSchemaViolation = &H0020000
Const adRecDBDeleted = &H0040000

'---- GetRowsOptionEnum Values ----
Const adGetRowsRest = -1

'---- PositionEnum Values ----
Const adPosUnknown = -1
Const adPosBOF = -2
Const adPosEOF = -3

'---- BookmarkEnum Values ----
Const adBookmarkCurrent = 0
Const adBookmarkFirst = 1
Const adBookmarkLast = 2

'---- MarshalOptionsEnum Values ----
Const adMarshalAll = 0
Const adMarshalModifiedOnly = 1

'---- AffectEnum Values ----
Const adAffectCurrent = 1
Const adAffectGroup = 2
Const adAffectAllChapters = 4

'---- ResyncEnum Values ----
Const adResyncUnderlyingValues = 1
Const adResyncAllValues = 2

'---- CompareEnum Values ----
Const adCompareLessThan = 0
Const adCompareEqual = 1
Const adCompareGreaterThan = 2
Const adCompareNotEqual = 3
Const adCompareNotComparable = 4

'---- FilterGroupEnum Values ----
Const adFilterNone = 0
Const adFilterPendingRecords = 1
Const adFilterAffectedRecords = 2
Const adFilterFetchedRecords = 3
Const adFilterConflictingRecords = 5

'---- SearchDirectionEnum Values ----
Const adSearchForward = 1
Const adSearchBackward = -1

'---- PersistFormatEnum Values ----
Const adPersistADTG = 0
Const adPersistXML = 1

'---- StringFormatEnum Values ----
Const adClipString = 2

'---- ConnectPromptEnum Values ----
Const adPromptAlways = 1
Const adPromptComplete = 2
Const adPromptCompleteRequired = 3
Const adPromptNever = 4

'---- ConnectModeEnum Values ----
Const adModeUnknown = 0
Const adModeRead = 1
Const adModeWrite = 2
Const adModeReadWrite = 3
Const adModeShareDenyRead = 4
Const adModeShareDenyWrite = 8
Const adModeShareExclusive = &Hc
Const adModeShareDenyNone = &H10
Const adModeRecursive = &H400000

'---- RecordCreateOptionsEnum Values ----
Const adCreateCollection = &H00002000
Const adCreateStructDoc = &H80000000
Const adCreateNonCollection = &H00000000
Const adOpenIfExists = &H02000000
Const adCreateOverwrite = &H04000000
Const adFailIfNotExists = -1

'---- RecordOpenOptionsEnum Values ----
Const adOpenRecordUnspecified = -1
Const adOpenOutput = &H00800000
Const adOpenAsync = &H00001000
Const adDelayFetchStream = &H00004000
Const adDelayFetchFields = &H00008000
Const adOpenExecuteCommand = &H00010000

'---- IsolationLevelEnum Values ----
Const adXactUnspecified = &Hffffffff
Const adXactChaos = &H00000010
Const adXactReadUncommitted = &H00000100
Const adXactBrowse = &H00000100
Const adXactCursorStability = &H00001000
Const adXactReadCommitted = &H00001000
Const adXactRepeatableRead = &H00010000
Const adXactSerializable = &H00100000
Const adXactIsolated = &H00100000

'---- XactAttributeEnum Values ----
Const adXactCommitRetaining = &H00020000
Const adXactAbortRetaining = &H00040000

'---- PropertyAttributesEnum Values ----
Const adPropNotSupported = &H0000
Const adPropRequired = &H0001
Const adPropOptional = &H0002
Const adPropRead = &H0200
Const adPropWrite = &H0400

'---- ErrorValueEnum Values ----
Const adErrProviderFailed = &Hbb8
Const adErrInvalidArgument = &Hbb9
Const adErrOpeningFile = &Hbba
Const adErrReadFile = &Hbbb
Const adErrWriteFile = &Hbbc
Const adErrNoCurrentRecord = &Hbcd
Const adErrIllegalOperation = &Hc93
Const adErrCantChangeProvider = &Hc94
Const adErrInTransaction = &Hcae
Const adErrFeatureNotAvailable = &Hcb3
Const adErrItemNotFound = &Hcc1
Const adErrObjectInCollection = &Hd27
Const adErrObjectNotSet = &Hd5c
Const adErrDataConversion = &Hd5d
Const adErrObjectClosed = &He78
Const adErrObjectOpen = &He79
Const adErrProviderNotFound = &He7a
Const adErrBoundToCommand = &He7b
Const adErrInvalidParamInfo = &He7c
Const adErrInvalidConnection = &He7d
Const adErrNotReentrant = &He7e
Const adErrStillExecuting = &He7f
Const adErrOperationCancelled = &He80
Const adErrStillConnecting = &He81
Const adErrInvalidTransaction = &He82
Const adErrUnsafeOperation = &He84
Const adwrnSecurityDialog = &He85
Const adwrnSecurityDialogHeader = &He86
Const adErrIntegrityViolation = &He87
Const adErrPermissionDenied = &He88
Const adErrDataOverflow = &He89
Const adErrSchemaViolation = &He8a
Const adErrSignMismatch = &He8b
Const adErrCantConvertvalue = &He8c
Const adErrCantCreate = &He8d
Const adErrColumnNotOnThisRow = &He8e
Const adErrURLIntegrViolSetColumns = &He8f
Const adErrURLDoesNotExist = &He8f
Const adErrTreePermissionDenied = &He90
Const adErrInvalidURL = &He91
Const adErrResourceLocked = &He92
Const adErrResourceExists = &He93
Const adErrCannotComplete = &He94
Const adErrVolumeNotFound = &He95
Const adErrOutOfSpace = &He96
Const adErrResourceOutOfScope = &He97
Const adErrUnavailable = &He98
Const adErrURLNamedRowDoesNotExist = &He99
Const adErrDelResOutOfScope = &He9a
Const adErrPropInvalidColumn = &He9b
Const adErrPropInvalidOption = &He9c
Const adErrPropInvalidValue = &He9d
Const adErrPropConflicting = &He9e
Const adErrPropNotAllSettable = &He9f
Const adErrPropNotSet = &Hea0
Const adErrPropNotSettable = &Hea1
Const adErrPropNotSupported = &Hea2
Const adErrCatalogNotSet = &Hea3
Const adErrCantChangeConnection = &Hea4
Const adErrFieldsUpdateFailed = &Hea5
Const adErrDenyNotSupported = &Hea6
Const adErrDenyTypeNotSupported = &Hea7
Const adErrProviderNotSpecified = &Hea9
Const adErrConnectionStringTooLong = &Heaa

'---- ParameterAttributesEnum Values ----
Const adParamSigned = &H0010
Const adParamNullable = &H0040
Const adParamLong = &H0080

'---- ParameterDirectionEnum Values ----
Const adParamUnknown = &H0000
Const adParamInput = &H0001
Const adParamOutput = &H0002
Const adParamInputOutput = &H0003
Const adParamReturnValue = &H0004

'---- CommandTypeEnum Values ----
Const adCmdUnknown = &H0008
Const adCmdText = &H0001
Const adCmdTable = &H0002
Const adCmdStoredProc = &H0004
Const adCmdFile = &H0100
Const adCmdTableDirect = &H0200

'---- EventStatusEnum Values ----
Const adStatusOK = &H0000001
Const adStatusErrorsOccurred = &H0000002
Const adStatusCantDeny = &H0000003
Const adStatusCancel = &H0000004
Const adStatusUnwantedEvent = &H0000005

'---- EventReasonEnum Values ----
Const adRsnAddNew = 1
Const adRsnDelete = 2
Const adRsnUpdate = 3
Const adRsnUndoUpdate = 4
Const adRsnUndoAddNew = 5
Const adRsnUndoDelete = 6
Const adRsnRequery = 7
Const adRsnResynch = 8
Const adRsnClose = 9
Const adRsnMove = 10
Const adRsnFirstChange = 11
Const adRsnMoveFirst = 12
Const adRsnMoveNext = 13
Const adRsnMovePrevious = 14
Const adRsnMoveLast = 15

'---- SchemaEnum Values ----
Const adSchemaProviderSpecific = -1
Const adSchemaAsserts = 0
Const adSchemaCatalogs = 1
Const adSchemaCharacterSets = 2
Const adSchemaCollations = 3
Const adSchemaColumns = 4
Const adSchemaCheckConstraints = 5
Const adSchemaConstraintColumnUsage = 6
Const adSchemaConstraintTableUsage = 7
Const adSchemaKeyColumnUsage = 8
Const adSchemaReferentialConstraints = 9
Const adSchemaTableConstraints = 10
Const adSchemaColumnsDomainUsage = 11
Const adSchemaIndexes = 12
Const adSchemaColumnPrivileges = 13
Const adSchemaTablePrivileges = 14
Const adSchemaUsagePrivileges = 15
Const adSchemaProcedures = 16
Const adSchemaSchemata = 17
Const adSchemaSQLLanguages = 18
Const adSchemaStatistics = 19
Const adSchemaTables = 20
Const adSchemaTranslations = 21
Const adSchemaProviderTypes = 22
Const adSchemaViews = 23
Const adSchemaViewColumnUsage = 24
Const adSchemaViewTableUsage = 25
Const adSchemaProcedureParameters = 26
Const adSchemaForeignKeys = 27
Const adSchemaPrimaryKeys = 28
Const adSchemaProcedureColumns = 29
Const adSchemaDBInfoKeywords = 30
Const adSchemaDBInfoLiterals = 31
Const adSchemaCubes = 32
Const adSchemaDimensions = 33
Const adSchemaHierarchies = 34
Const adSchemaLevels = 35
Const adSchemaMeasures = 36
Const adSchemaProperties = 37
Const adSchemaMembers = 38
Const adSchemaTrustees = 39
Const adSchemaFunctions = 40
Const adSchemaActions = 41
Const adSchemaCommands = 42
Const adSchemaSets = 43

'---- FieldStatusEnum Values ----
Const adFieldOK = 0
Const adFieldCantConvertValue = 2
Const adFieldIsNull = 3
Const adFieldTruncated = 4
Const adFieldSignMismatch = 5
Const adFieldDataOverflow = 6
Const adFieldCantCreate = 7
Const adFieldUnavailable = 8
Const adFieldPermissionDenied = 9
Const adFieldIntegrityViolation = 10
Const adFieldSchemaViolation = 11
Const adFieldBadStatus = 12
Const adFieldDefault = 13
Const adFieldIgnore = 15
Const adFieldDoesNotExist = 16
Const adFieldInvalidURL = 17
Const adFieldResourceLocked = 18
Const adFieldResourceExists = 19
Const adFieldCannotComplete = 20
Const adFieldVolumeNotFound = 21
Const adFieldOutOfSpace = 22
Const adFieldCannotDeleteSource = 23
Const adFieldReadOnly = 24
Const adFieldResourceOutOfScope = 25
Const adFieldAlreadyExists = 26
Const adFieldPendingInsert = &H10000
Const adFieldPendingDelete = &H20000
Const adFieldPendingChange = &H40000
Const adFieldPendingUnknown = &H80000
Const adFieldPendingUnknownDelete = &H100000

'---- SeekEnum Values ----
Const adSeekFirstEQ = &H1
Const adSeekLastEQ = &H2
Const adSeekAfterEQ = &H4
Const adSeekAfter = &H8
Const adSeekBeforeEQ = &H10
Const adSeekBefore = &H20

'---- ADCPROP_UPDATECRITERIA_ENUM Values ----
Const adCriteriaKey = 0
Const adCriteriaAllCols = 1
Const adCriteriaUpdCols = 2
Const adCriteriaTimeStamp = 3

'---- ADCPROP_ASYNCTHREADPRIORITY_ENUM Values ----
Const adPriorityLowest = 1
Const adPriorityBelowNormal = 2
Const adPriorityNormal = 3
Const adPriorityAboveNormal = 4
Const adPriorityHighest = 5

'---- ADCPROP_AUTORECALC_ENUM Values ----
Const adRecalcUpFront = 0
Const adRecalcAlways = 1

'---- ADCPROP_UPDATERESYNC_ENUM Values ----
Const adResyncNone = 0
Const adResyncAutoIncrement = 1
Const adResyncConflicts = 2
Const adResyncUpdates = 4
Const adResyncInserts = 8
Const adResyncAll = 15

'---- MoveRecordOptionsEnum Values ----
Const adMoveUnspecified = -1
Const adMoveOverWrite = 1
Const adMoveDontUpdateLinks = 2
Const adMoveAllowEmulation = 4

'---- CopyRecordOptionsEnum Values ----
Const adCopyUnspecified = -1
Const adCopyOverWrite = 1
Const adCopyAllowEmulation = 4
Const adCopyNonRecursive = 2

'---- StreamTypeEnum Values ----
Const adTypeBinary = 1
Const adTypeText = 2

'---- LineSeparatorEnum Values ----
Const adLF = 10
Const adCR = 13
Const adCRLF = -1

'---- StreamOpenOptionsEnum Values ----
Const adOpenStreamUnspecified = -1
Const adOpenStreamAsync = 1
Const adOpenStreamFromRecord = 4

'---- StreamWriteEnum Values ----
Const adWriteChar = 0
Const adWriteLine = 1

'---- SaveOptionsEnum Values ----
Const adSaveCreateNotExist = 1
Const adSaveCreateOverWrite = 2

'---- FieldEnum Values ----
Const adDefaultStream = -1
Const adRecordURL = -2

'---- StreamReadEnum Values ----
Const adReadAll = -1
Const adReadLine = -2

'---- RecordTypeEnum Values ----
Const adSimpleRecord = 0
Const adCollectionRecord = 1
Const adStructDoc = 2
%>

ADO DataTypeEnum

ADO 2.8 API Reference

DataTypeEnum
Specifies the data type of a Field, Parameter, or Property. The corresponding OLE DB type indicator is shown in parentheses in the description column of the following table. For more information about OLE DB data types, see Chapter 13: Data Types in OLE DB and Appendix A: Data Types of the OLE DB Programmer’s Reference. 继续阅读

如何使用 ADO Stream 对象访问和修改 SQL Server BLOB 数据

如何使用 ADO Stream 对象访问和修改 SQL Server BLOB 数据
文章 ID : 258038

概要
使用 ActiveX 数据对象 (ADO) 2.5 中引入的 Stream 对象可以大大简化访问和修改 SQL Server 数据库中的二进制大对象 (BLOB) 数据需要编写的代码。在以前版本的 ADO(2.0、2.1 和 2.1 SP2)中使用 Field Object 的 GetChunk 和 AppendChunk 方法以固定块区大小从 BLOB 列中读取 BLOB 数据,或将 BLOB 数据写入其中时,必须要小心。现在 ADO 2.5 中提供了一种替代方法。本文包含的代码示例演示如何使用 Stream 对象编写程序来执行以下常见任务:
• 将 SQL Server Image 列中存储的数据保存到硬盘上的文件中。
• 将 .gif 文件的内容移动到 SQL Server 表的 Image 列中。 继续阅读