Recordset Object (DAO)
A Recordset object represents the records in a base table or the records that result from running a query.
You use Recordset objects to manipulate data in a database at the record level. When you use DAO objects, you manipulate data almost entirely using Recordset objects. All Recordset objects are constructed using records (rows) and fields (columns). There are five types of Recordset objects:
Table-type Recordset— representation in code of a base table that you can use to add, change, or delete records from a single database table (Microsoft Access workspaces only).
Dynaset-type Recordset— the result of a query that can have updatable records. A dynaset-type Recordset object is a dynamic set of records that you can use to add, change, or delete records from an underlying database table or tables. A dynaset-type Recordset object can contain fields from one or more tables in a database. This type corresponds to an ODBC keyset cursor.
Snapshot-type Recordset— a static copy of a set of records that you can use to find data or generate reports. A snapshot-type Recordset object can contain fields from one or more tables in a database but can't be updated. This type corresponds to an ODBC static cursor.
Forward-only-type Recordset— identical to a snapshot except that no cursor is provided. You can only scroll forward through records. This improves performance in situations where you only need to make a single pass through a result set. This type corresponds to an ODBC forward-only cursor.
Dynamic-type Recordset— a query result set from one or more base tables in which you can add, change, or delete records from a row-returning query. Further, records other users add, delete, or edit in the base tables also appear in your Recordset. This type corresponds to an ODBC dynamic cursor (ODBCDirect workspaces only).
ODBCDirect workspaces are not supported in Microsoft Access 2010. Use ADO if you want to access external data sources without using the Microsoft Access database engine.
You can choose the type of Recordset object you want to create using the type argument of the OpenRecordset method.
In a Microsoft Access workspace, if you don't specify a type, DAO attempts to create the type of Recordset with the most functionality available, starting with table. If this type isn't available, DAO attempts a dynaset, then a snapshot, and finally a forward-only type Recordset object.
In an ODBCDirect workspace, if you don't specify a type, DAO attempts to create the type of Recordset with the fastest query response, starting with forward-only. If this type isn't available, DAO attempts a snapshot, then a dynaset, and finally a dynamic- type Recordset object.
When creating a Recordset object using a non-linked TableDef object in a Microsoft Access workspace, table-type Recordset objects are created. Only dynaset-type or snapshot-type Recordset objects can be created with linked tables or tables in Microsoft Access database engine-connected ODBC databases.
A new Recordset object is automatically added to the Recordsets collection when you open the object, and is automatically removed when you close it.
If you use variables to represent a Recordset object and the Database object that contains the Recordset, make sure the variables have the same scope, or lifetime. For example, if you declare a public variable that represents a Recordset object, make sure the variable that represents the Database containing the Recordset is also public, or is declared in a Sub or Function procedure using the Static keyword.
You can create as many Recordset object variables as needed. Different Recordset objects can access the same tables, queries, and fields without conflicting.
Dynaset–, snapshot–, and forward–only–type Recordset objects are stored in local memory. If there isn't enough space in local memory to store the data, the Microsoft Access database engine saves the additional data to TEMP disk space. If this space is exhausted, a trappable error occurs.
When you create a Recordset object, the current record is positioned to the first record if there are any records. If there are no records, the RecordCount property setting is 0, and the BOF and EOF property settings are True.
You can use the MoveNext, MovePrevious, MoveFirst, and MoveLast methods to reposition the current record. Forward–only–type Recordset objects support only the MoveNext method. When using the Move methods to visit each record (or "walk" through the Recordset), you can use the BOF and EOF properties to check for the beginning or end of the Recordset object.
With dynaset- and snapshot-type Recordset objects in a Microsoft Access workspace, you can also use the Find methods, such as FindFirst, to locate a specific record based on criteria. If the record isn't found, the NoMatch property is set to True. For table-type Recordset objects, you can scan records using the Seek method.
The Type property indicates the type of Recordset object created, and the Updatable property indicates whether you can change the object's records.
Information about the structure of a base table, such as the names and data types of each Field object and any Index objects, is stored in a TableDef object.
To refer to a Recordset object in a collection by its ordinal number or by its Name property setting, use any of the following syntax forms:
You can open a Recordset object from the same data source or database more than once, creating duplicate names in the Recordsets collection. You should assign Recordset objects to object variables and refer to them by variable name.
This example demonstrates Recordset objects and the Recordsets collection by opening four different types of Recordsets, enumerating the Recordsets collection of the current Database, and enumerating the Properties collection of each Recordset.
Sub RecordsetX() Dim dbsNorthwind As Database Dim rstTable As Recordset Dim rstDynaset As Recordset Dim rstSnapshot As Recordset Dim rstForwardOnly As Recordset Dim rstLoop As Recordset Dim prpLoop As Property Set dbsNorthwind = OpenDatabase("Northwind.mdb") With dbsNorthwind ' Open one of each type of Recordset object. Set rstTable = .OpenRecordset("Categories", _ dbOpenTable) Set rstDynaset = .OpenRecordset("Employees", _ dbOpenDynaset) Set rstSnapshot = .OpenRecordset("Shippers", _ dbOpenSnapshot) Set rstForwardOnly = .OpenRecordset _ ("Employees", dbOpenForwardOnly) Debug.Print "Recordsets in Recordsets " & _ "collection of dbsNorthwind" ' Enumerate Recordsets collection. For Each rstLoop In .Recordsets With rstLoop Debug.Print " " & .Name ' Enumerate Properties collection of each ' Recordset object. Trap for any ' properties whose values are invalid in ' this context. For Each prpLoop In .Properties On Error Resume Next If prpLoop <> "" Then Debug.Print _ " " & prpLoop.Name & _ " = " & prpLoop On Error GoTo 0 Next prpLoop End With Next rstLoop rstTable.Close rstDynaset.Close rstSnapshot.Close rstForwardOnly.Close .Close End With End Sub
This example uses the OpenRecordset method to open five different Recordset objects and display their contents. The OpenRecordsetOutput procedure is required for this procedure to run.
Sub OpenRecordsetX() Dim wrkAcc As Workspace Dim wrkODBC As Workspace Dim dbsNorthwind As Database Dim conPubs As Connection Dim rstTemp As Recordset Dim rstTemp2 As Recordset ' Open Microsoft Access and ODBCDirect workspaces, Microsoft ' Access database, and ODBCDirect connection. Set wrkAcc = CreateWorkspace("", "admin", "", dbUseJet) Set wrkODBC = CreateWorkspace("", "admin", "", dbUseODBC) Set dbsNorthwind = wrkAcc.OpenDatabase("Northwind.mdb") ' Note: The DSN referenced below must be set to ' use Microsoft Windows NT Authentication Mode to ' authorize user access to the Microsoft SQL Server. Set conPubs = wrkODBC.OpenConnection("", , , _ "ODBC;DATABASE=pubs;DSN=Publishers") ' Open five different Recordset objects and display the ' contents of each. Debug.Print "Opening forward-only-type recordset " & _ "where the source is a QueryDef object..." Set rstTemp = dbsNorthwind.OpenRecordset( _ "Ten Most Expensive Products", dbOpenForwardOnly) OpenRecordsetOutput rstTemp Debug.Print "Opening read-only dynaset-type " & _ "recordset where the source is an SQL statement..." Set rstTemp = dbsNorthwind.OpenRecordset( _ "SELECT * FROM Employees", dbOpenDynaset, dbReadOnly) OpenRecordsetOutput rstTemp ' Use the Filter property to retrieve only certain ' records with the next OpenRecordset call. Debug.Print "Opening recordset from existing " & _ "Recordset object to filter records..." rstTemp.Filter = "LastName >= 'M'" Set rstTemp2 = rstTemp.OpenRecordset() OpenRecordsetOutput rstTemp2 Debug.Print "Opening dynamic-type recordset from " & _ "an ODBC connection..." Set rstTemp = conPubs.OpenRecordset( _ "SELECT * FROM stores", dbOpenDynamic) OpenRecordsetOutput rstTemp ' Use the StillExecuting property to determine when the ' Recordset is ready for manipulation. Debug.Print "Opening snapshot-type recordset based " & _ "on asynchronous query to ODBC connection..." Set rstTemp = conPubs.OpenRecordset("publishers", _ dbOpenSnapshot, dbRunAsync) Do While rstTemp.StillExecuting Debug.Print " [still executing...]" Loop OpenRecordsetOutput rstTemp rstTemp.Close dbsNorthwind.Close conPubs.Close wrkAcc.Close wrkODBC.Close End Sub Sub OpenRecordsetOutput(rstOutput As Recordset) ' Enumerate the specified Recordset object. With rstOutput Do While Not .EOF Debug.Print , .Fields(0), .Fields(1) .MoveNext Loop End With End Sub
This example opens a dynamic-type Recordset object and enumerates its records.
Sub dbOpenDynamicX() Dim wrkMain As Workspace Dim conMain As Connection Dim qdfTemp As QueryDef Dim rstTemp As Recordset Dim strSQL As String Dim intLoop As Integer ' Create ODBC workspace and open connection to ' SQL Server database. Set wrkMain = CreateWorkspace("ODBCWorkspace", _ "admin", "", dbUseODBC) ' Note: The DSN referenced below must be configured to ' use Microsoft Windows NT Authentication Mode to ' authorize user access to the Microsoft SQL Server. Set conMain = wrkMain.OpenConnection("Publishers", _ dbDriverNoPrompt, False, _ "ODBC;DATABASE=pubs;DSN=Publishers") ' Open dynamic-type recordset. Set rstTemp = _ conMain.OpenRecordset("authors", _ dbOpenDynamic) With rstTemp Debug.Print "Dynamic-type recordset: " & .Name ' Enumerate records. Do While Not .EOF Debug.Print " " & !au_lname & ", " & _ !au_fname .MoveNext Loop .Close End With conMain.Close wrkMain.Close End Sub
This example opens a dynaset-type Recordset and shows the extent to which its fields are updatable.
Sub dbOpenDynasetX() Dim dbsNorthwind As Database Dim rstInvoices As Recordset Dim fldLoop As Field Set dbsNorthwind = OpenDatabase("Northwind.mdb") Set rstInvoices = _ dbsNorthwind.OpenRecordset("Invoices", dbOpenDynaset) With rstInvoices Debug.Print "Dynaset-type recordset: " & .Name If .Updatable Then Debug.Print " Updatable fields:" ' Enumerate Fields collection of dynaset-type ' Recordset object, print only updatable ' fields. For Each fldLoop In .Fields If fldLoop.DataUpdatable Then Debug.Print " " & fldLoop.Name End If Next fldLoop End If .Close End With dbsNorthwind.Close End Sub
This example opens a forward-only-type Recordset, demonstrates its read-only characteristics, and steps through the Recordset with the MoveNext method.
Sub dbOpenForwardOnlyX() Dim dbsNorthwind As Database Dim rstEmployees As Recordset Dim fldLoop As Field Set dbsNorthwind = OpenDatabase("Northwind.mdb") ' Open a forward-only-type Recordset object. Only the ' MoveNext and Move methods may be used to navigate ' through the recordset. Set rstEmployees = _ dbsNorthwind.OpenRecordset("Employees", _ dbOpenForwardOnly) With rstEmployees Debug.Print "Forward-only-type recordset: " & _ .Name & ", Updatable = " & .Updatable Debug.Print " Field - DataUpdatable" ' Enumerate Fields collection, printing the Name and ' DataUpdatable properties of each Field object. For Each fldLoop In .Fields Debug.Print " " & _ fldLoop.Name & " - " & fldLoop.DataUpdatable Next fldLoop Debug.Print " Data" ' Enumerate the recordset. Do While Not .EOF Debug.Print " " & !FirstName & " " & _ !LastName .MoveNext Loop .Close End With dbsNorthwind.Close End Sub
This example opens a snapshot-type Recordset and demonstrates its read-only characteristics.
Sub dbOpenSnapshotX() Dim dbsNorthwind As Database Dim rstEmployees As Recordset Dim prpLoop As Property Set dbsNorthwind = OpenDatabase("Northwind.mdb") Set rstEmployees = _ dbsNorthwind.OpenRecordset("Employees", _ dbOpenSnapshot) With rstEmployees Debug.Print "Snapshot-type recordset: " & _ .Name ' Enumerate the Properties collection of the ' snapshot-type Recordset object, trapping for ' any properties whose values are invalid in ' this context. For Each prpLoop In .Properties On Error Resume Next Debug.Print " " & _ prpLoop.Name & " = " & prpLoop On Error Goto 0 Next prpLoop .Close End With dbsNorthwind.Close End Sub
This example opens a table-type Recordset, sets its Index property, and enumerates its records.
Sub dbOpenTableX() Dim dbsNorthwind As Database Dim rstEmployees As Recordset Set dbsNorthwind = OpenDatabase("Northwind.mdb") ' dbOpenTable is default. Set rstEmployees = _ dbsNorthwind.OpenRecordset("Employees") With rstEmployees Debug.Print "Table-type recordset: " & .Name ' Use predefined index. .Index = "LastName" Debug.Print " Index = " & .Index ' Enumerate records. Do While Not .EOF Debug.Print " " & !LastName & ", " & _ !FirstName .MoveNext Loop .Close End With dbsNorthwind.Close End Sub
The following example shows how to use the Seek method to find a record in a linked table.
Sub TestSeek() ' Get the path to the external database that contains ' the tblCustomers table we're going to search. Dim strMyExternalDatabase Dim dbs As DAO.Database Dim dbsExt As DAO.Database Dim rst As DAO.Recordset Dim tdf As DAO.TableDef Set dbs = CurrentDb() Set tdf = dbs.TableDefs("tblCustomers") strMyExternalDatabase = Mid(tdf.Connect, 11) 'Open the database that contains the table that is linked Set dbsExt = OpenDatabase(strMyExternalDatabase) 'Open a table-type recordset against the external table Set rst = dbsExt.OpenRecordset("tblCustomers", dbOpenTable) 'Specify which index to search on rst.Index = "PrimaryKey" 'Specify the criteria rst.Seek "=", 123 'Check the result If rst.NoMatch Then MsgBox "Record not found." Else MsgBox "Customer name: " & rst!CustName End If rst.Close dbs.Close dbsExt.Close Set rst = Nothing Set tdf = Nothing Set dbs = Nothing End Sub
The following example shows how to open a Recordset that is based on a parameter query.
Dim dbs As DAO.Database Dim qdf As DAO.QueryDef Dim rst As DAO.Recordset Set dbs = CurrentDb 'Get the parameter query Set qfd = dbs.QueryDefs("qryMyParameterQuery") 'Supply the parameter value qdf.Parameters("EnterStartDate") = Date qdf.Parameters("EnterEndDate") = Date + 7 'Open a Recordset based on the parameter query Set rst = qdf.OpenRecordset()
The following example shows how to open a Recordset based on a table or a query.
Dim dbs As DAO.Database Dim rsTable As DAO.Recordset Dim rsQuery As DAO.Recordset Set dbs = CurrentDb 'Open a table-type Recordset Set rsTable = dbs.OpenRecordset("Table1", dbOpenTable) 'Open a dynaset-type Recordset using a saved query Set rsQuery = dbs.OpenRecordset("qryMyQuery", dbOpenDynaset)
The following example shows how to open a Recordset based on a Structured Query Language (SQL) statement.
Dim dbs As DAO.Database Dim rsSQL As DAO.Recordset Dim strSQL As String Set dbs = CurrentDb 'Open a snapshot-type Recordset based on an SQL statement strSQL = "SELECT * FROM Table1 WHERE Field2 = 33" Set rsSQL = dbs.OpenRecordset(strSQL, dbOpenSnapshot)
The following example shows how to use the FindFirst and FindNext methods to find a record in a Recordset.
Sub FindOrgName() Dim dbs As DAO.Database Dim rst As DAO.Recordset 'Get the database and Recordset Set dbs = CurrentDb Set rst = dbs.OpenRecordset("tblCustomers") 'Search for the first matching record rst.FindFirst "[OrgName] LIKE '*parts*'" 'Check the result If rst.NoMatch Then MsgBox "Record not found." GotTo Cleanup Else Do While Not rst.NoMatch MsgBox "Customer name: " & rst!CustName rst.FindNext "[OrgName] LIKE '*parts*'" Loop 'Search for the next matching record rst.FindNext "[OrgName] LIKE '*parts*'" End If Cleanup: rst.Close Set rst = Nothing Set dbs = Nothing End Sub
The following example shows how to copy the results of a query to a worksheet in a new Microsoft Excel workbook.
Public Sub CopyDataFromQuery( _ xlApp As Excel.Application, _ strQueryName As String) ' If the xlApp object exists If Not xlApp Is Nothing Then ' If the Workbook exists If xlApp.Workbooks.Count = 1 Then ' Create Recrodset Object from the Query Dim rsQuery As DAO.Recordset Set rsQuery = Application.CurrentDb.OpenRecordset(strQueryName) ' Get the Cells object Dim Cells As Object Set Cells = xlApp.Workbooks(1).ActiveSheet.Cells ' Copy the Data from the Query into the Sheet Cells.CopyFromRecordset rsQuery End If End If End Sub