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.NET/ASP.NET/C#/VB.NET PDF Document SDKwhich is discussed in more detail in 15. The first function for querying the database is called GetCategories and simply returns the IDs and names of all the categories in the database; the second one is called GetProducts and it returns information about products in a specified category passed as a parameter. Note that when referring to a concrete variable in the F# Linq query, you must use the paragraph symbol ( ) to splice it as such into the query representation. Now, let s look at the Category.aspx file, shown in Listing 14-8, which contains the ASP.NET markup for viewing products in a specified category. You can specify the category that will be displayed as an argument in the URL, for example, Category.aspx id=3. Listing 14-8. Category.aspx: The ASP.NET Page for Displaying Products in a Category <%@ Page Language="F#" %> <html> <head runat="server"> <title>Category Listing</title> </head> <body> <form runat="server"> <!-- Unordered list of products using ASP.NET Repeater --> <ul> <asp:Repeater runat="server" id="rptProducts" DataSourceID="nwindProducts"> <ItemTemplate> <li><%# this.Eval("ProductName") %> (price: <%# this.Eval("Price") %>)</li> </ItemTemplate> </asp:Repeater> </ul> <!-- ASP.NET DataSource control for loading the data --> <asp:ObjectDataSource id="nwindProducts" runat="server" TypeName="FSharpWeb.DataSource" SelectMethod="GetProducts"> <SelectParameters> <asp:QueryStringParameter Name="categoryId" Type="Int32" QueryStringField="id" DefaultValue="0"/> </SelectParameters> </asp:ObjectDataSource> </form> </body> </html> The ASP.NET markup in Listing 14-8 is not using any code-behind code, because all we need for accessing the data is already available in the module we wrote in Listing 14-7. The first part of the markup declares the ASP.NET Repeater control including an ItemTemplate that will be used for rendering a single product. Similarly to the earlier examples, we use the Eval construct for accessing the data, but in this example the product is represented using the ProductInfo record declared earlier, so we can use the appropriate labels as an argument to the Eval function. qr code vb.net open source, winforms barcode generator, winforms code 128, vb.net gs1 128, vb.net ean-13 barcode, codigo fuente pdf417 vb.net, itextsharp remove text from pdf c#, replace text in pdf using itextsharp in c#, vb.net data matrix barcode, itextsharp remove text from pdf c#,Inserting Objects Using the setObject() Method of PreparedStatement The second method involves using the standard setObject() method of the Prepared Statement interface (or the CallableStatement interface), as demonstrated by the following _demoInsertUsingSetObject() method: private static void _demoInsertUsingSetObject( Connection connection) throws SQLException, ClassNotFoundException { PreparedStatement pstmt = null; try { MyAddressORAData myAddress = new MyAddressORAData(); myAddress.setLine1("134 Ferry Rd"); myAddress.setLine2( "Apt # 24"); myAddress.setStreet( "Crypton St." ); myAddress.setCity( "Dallas"); myAddress.setState( "TX" ); myAddress.setZip( "75201" ); String insertStmt = "insert into address_table values( )"; pstmt = connection.prepareStatement ( insertStmt ); pstmt.setObject (1, myAddress ); int rows = pstmt.executeUpdate(); System.out.println ( "Inserted " + rows + " row(s) " ); connection.commit(); } finally { JDBCUtil.close( pstmt ); } } Updating Objects As in the case of a SQLData-based implementation, you update an object by selecting it into memory, changing the in-memory Java object as required, and using the Java object to update the object value in the database, as shown in the following code. The phenomenon of lost updates mentioned earlier is applicable here, too; hence we use the phrase for update nowait during the select. The rest of the code uses concepts covered in earlier chapter sections. private static void _demoUpdate( Connection connection) throws SQLException, ClassNotFoundException { OraclePreparedStatement opstmt = null; PreparedStatement pstmt = null; OracleResultSet orset = null; try { MyAddressORAData myAddress = null; Pre and Post events have been added for this event as well In ASP NET 1x, this event is the last chance for you to extend the pipeline before an instance of the HttpHandler is created for the request With the addition of the Pre and Post MapRequestHandler events (below), this is no longer the case, and this event is now properly the domain of the request cache This is the entry point for the Cache module The Cache module is the extension to the runtime that manages sending and retrieving pages from the cache You may already be familiar with the OutputCache directive <%@ OutputCache duration="5" VaryByParam="*" %>. String selectStmt = "select value(a) from address_table a"+ " where line1 = for update nowait"; pstmt = connection.prepareStatement ( selectStmt ); pstmt.setString( 1, "145 Apt # 7" ); orset = (OracleResultSet) pstmt.executeQuery(); if ( orset.next() ) { myAddress = (MyAddressORAData) orset.getORAData(1, MyAddressORAData.getORADataFactory() ); myAddress.setStreet ( "Wonderful St" ); String updateStmt = "update address_table a" + " set value(a) = " + " where a.line1 = "; opstmt = (OraclePreparedStatement) connection.prepareStatement ( updateStmt ); opstmt.setORAData (1, myAddress ); opstmt.setString (2, "145 Apt # 7" ); int rows = opstmt.executeUpdate(); System.out.println ( "Updated " + rows + " rows " ); } connection.commit(); } finally { JDBCUtil.close( orset ); JDBCUtil.close( opstmt ); } } Deleting Objects There is nothing special about deleting an object. It is a simple relational statement, as illustrated in the following _demoDelete() method: private static void _demoDelete( Connection connection) throws SQLException, ClassNotFoundException { PreparedStatement pstmt = null; try { String deleteStmt = "delete address_table a" + " where a.line1 like "; pstmt = connection.prepareStatement ( deleteStmt ); pstmt.setString (1, "Mountain View" ); int rows = pstmt.executeUpdate(); System.out.println ( "Deleted " + rows + " row(s) " ); connection.commit(); } The second part of the markup is far more interesting; it declares an ASPNET ObjectDataSource control, which is a nonvisual control, meaning it will not generate any HTML code It serves simply as a source of data for the Repeater control in the first part, and as you can see, these two are linked together using the DataSourceID attribute of the Repeater control, which is set to the ID of the data source control The ObjectDataSource is configured using the TypeName attribute, which specifies the NET type that implements the functionality (in our case we re using an F# module instead of an object type) The attribute SelectMethod sets a name of the method (or a function in our case) that should be called when the data is required. finally { JDBCUtil.close( pstmt ); } } } Now that you know how to use the SQLData interface and the Oracle extension interfaces ORAData and ORADataFactory, let s compare the two approaches.
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