propertiesmethodsevents.html

DAOOCXOnly深入ADO.NET开发高级数据访问技术

							<TD width="71%"><B>Description</B></TD>
						</TR>
						<TR vAlign=top>
							<TD width="29%"><B>True</B></TD>
							<TD width="71%">Opens the database with read-only access.</TD>
						</TR>
						<TR vAlign=top>
							<TD width="29%"><B>False</B></TD>
							<TD width="71%">Default. Opens the database with read/write access.</TD>
						</TR>
					</TABLE>
					<A HREF="#Top">Return to Top</A><HR>
				</TD>
			<tr>
			<TR>
				<td width="100%" align="left" valign="top">
					<font color="#000000" size="5"><span style="font-size:16;line-height:18px;">
					<a name="LockType"><b><font color="#191970">LockType</font></b></a>
					<P>Specifies the lock type used.</P>
					<TABLE cols=2 cellPadding=5 rules=rows border=1 frame=below>
						<TR vAlign=top>
							<TD class=label width="50%"><B>Constant</B></TD>
							<TD class=label width="50%"><B>Description</B></TD>
						</TR>
						<TR vAlign=top>
							<TD width="50%"><B>dbOptimistic</B></TD>
							<TD width="50%">Default. Optimistic concurrency based on record ID. Cursor compares record ID in old and new records to determine if changes have been made since the record was last accessed.</TD>
						</TR>
						<TR vAlign=top>
							<TD width="50%"><B>dbOptimisticBatch</B></TD>
							<TD width="50%">Enables batch optimistic updating. The WorkSpaceType must be set to <b>dbUseODBC</b>.</TD>
						</TR>
						<TR vAlign=top>
							<TD width="50%"><B>dbOptimisticValue</B></TD>
							<TD width="50%">Uses optimistic concurrency based on row values. The WorkSpaceType must be set to <b>dbUseODBC</b>.</TD>
						</TR>
						<TR vAlign=top>
							<TD width="50%"><B>dbPessimistic</B></TD>
							<TD width="50%">Uses pessimistic locking to determine how changes are made to the Recordset in a multiuser environment. The page containing the record you're editing is locked as soon as you any editing is done.</TD>
						</TR>
					</TABLE>
					<A HREF="#Top">Return to Top</A><HR>
				</td>
			</tr>
			<tr>
				<td width="100%" align="left" valign="top">
					<font color="#000000" size="5"><span style="font-size:16;line-height:18px;">
					<a name="Recordset"><b><font color="#191970">Recordset (Object)</font></b></a>
					<P>You can set or retrieve the current recordset being used by the Data Control using this Object Property. It represents an open DAO recordset.</P>
					<P>The Object property is very useful when you want to set the Data Control to another recordset.</P>
					<P><B>Syntax Example:</B></P>
					<P><b>Set</b> SCIROCCODAODataControl.<b>Recordset</b> = MyRecordset</P>
					<A HREF="#Top">Return to Top</A><HR>
				</td>
			</tr>	
			<tr>
				<td width="100%" align="left" valign="top">
					<font color="#000000" size="5"><span style="font-size:16;line-height:18px;">
					<a name="RecordsetOptions"><b><font color="#191970">RecordsetOptions</font></b></a>
					<P>Optional. A combination of constants that specify characteristics of the new Recordset, as listed below.</P>
					<P>You can use a combination of the following constants for the <I>RecordsetOptions</I> argument.</P>
					<TABLE cols=2 cellPadding=5 rules=rows border=1 frame=below>
						<TR vAlign=top>
							<TD width="39%"><B>Constant</B></TD>
							<TD width="61%"><B>Description</B></TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbAppendOnly</B></TD>
							<TD width="61%">Allows users to append new records to the <B>Recordset</B>, but 
							prevents them from editing or deleting existing records. (Microsoft Jet only)</TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbSQLPassThrough</B></TD>
							<TD width="61%">Passes an SQL statement to a Microsoft Jet-connected ODBC data source</A> 
							for processing (Microsoft Jet snapshot-type <B>Recordset</B> only).</TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbSeeChanges</B></TD>
							<TD width="61%">Generates a run-time error</A> if one 
							user is changing data that another user is editing (Microsoft Jet dynaset-type 
							<B>Recordset</B> only). This is useful in applications where multiple users have 
							simultaneous read/write access to the same data. </TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbDenyWrite</B></TD>
							<TD width="61%">Prevents other users from modifying or adding records (Microsoft 
							Jet <B>Recordset</B> objects only).</TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbDenyRead</B></TD>
							<TD width="61%">Prevents other users from reading data in a table (Microsoft Jet 
							table-type <B>Recordset</B> only).</TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbForwardOnly</B></TD>
							<TD width="61%">Creates a forward-only <B>Recordset</B> (Microsoft Jet 
							snapshot-type <B>Recordset </B>only). It is provided only for backward 
							compatibility, and you should use the <B>dbOpenForwardOnly</B> constant in the 
							<I>type</I> argument instead of using this option. </TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbReadOnly</B></TD>
							<TD width="61%">Prevents users from making changes to the <B>Recordset 
							</B>(Microsoft Jet only). The <B>dbReadOnly</B> constant in the <I>lockedits</I> 
							argument replaces this option, which is provided only for backward 
							compatibility.</TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbRunAsync</B></TD>
							<TD width="61%">Runs an asynchronous query (ODBCDirect workspaces only). </TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbExecDirect</B></TD>
							<TD width="61%">Runs a query by skipping <B>SQLPrepare</B> and directly calling 
							<B>SQLExecDirect</B> (ODBCDirect workspaces only). Use this option only when 
							you抮e not opening a <B>Recordset</B> based on a parameter query. For more information, see 
							the "Microsoft ODBC 3.0 Programmer抯 Reference."</TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbInconsistent</B></TD>
							<TD width="61%">Allows inconsistent updates 
							(Microsoft Jet dynaset-type and snapshot-type <B>Recordset</B> objects 
							only).</TD>
						</TR>
						<TR vAlign=top>
							<TD width="39%"><B>dbConsistent</B></TD>
							<TD width="61%">Allows only consistent updates 
							(Microsoft Jet dynaset-type and snapshot-type <B>Recordset</B> objects only).</TD>
						</TR>
					</TABLE>
					<A HREF="#Top">Return to Top</A><HR>
				</td>
			<tr>
			<TR>
				<td width="100%" align="left" valign="top">
					<font color="#000000" size="5"><span style="font-size:16;line-height:18px;">
					<a name="RecordsetType"><b><font color="#191970">RecordsetType</font></b></a>	
					<P>Specifies the type of recordset used by the control.</P>
					<P>You can use one of the following constants for the <I>RecordsetType</I> argument.</P>
					<TABLE cellPadding=5 rules=rows border=1 frame=below>
						<TR vAlign=top>
							<TD width="43%"><B>Constant</B></TD>
							<TD width="57%"><B>Description</B></TD></TR>
						<TR vAlign=top>
							<TD width="43%"><B>dbOpenTable</B></TD>
							<TD width="57%">Opens a table-type <B>Recordset</B> object (Microsoft Jet workspaces only).</TD>
						</TR>
						<TR vAlign=top>
							<TD width="43%"><B>dbOpenDynamic</B></TD>
							<TD width="57%">Opens a dynamic-type <B>Recordset</B> object, which is similar 
							to an ODBC dynamic cursor. (ODBCDirect workspaces only)</TD>
						</TR>
						<TR vAlign=top>
							<TD width="43%"><B>dbOpenDynaset</B></TD>
							<TD width="57%">Default. Opens a dynaset-type <B>Recordset</B> object, which is similar 
							to an ODBC keyset cursor.</TD>
						</TR>
						<TR vAlign=top>
							<TD width="43%"><B>dbOpenSnapshot</B></TD>
							<TD width="57%">Opens a snapshot-type <B>Recordset</B> object, which is similar 
							to an ODBC static cursor.</TD>
						</TR>
						<TR vAlign=top>
							<TD width="43%"><B>dbOpenForwardOnly</B>