vb.net code to print barcode Using Dynamic SQL in Java

Create PDF 417 in Java Using Dynamic SQL

Using Dynamic SQL
PDF 417 Creator In Java
Using Barcode drawer for Java Control to generate, create PDF417 image in Java applications.
www.OnBarcode.com
Scanning PDF-417 2d Barcode In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
property into the DAO layer (see chapter 10) and call the appropriate select statement based on the parentCategoryId s null state. Although handling this simple example without Dynamic SQL would not have inconvenienced us that much, the real value of Dynamic SQL becomes evident when several different combinations of properties result in an exponential growth of statement possibilities. By using Dynamic SQL, we increase mapped statement reuse and avoid having to write multiple static SQL statements. Now that we have gained a good context for the usage and power of Dynamic SQL, let s delve deeper into exploring all the tags and their attributes.
Linear Generator In Java
Using Barcode encoder for Java Control to generate, create Linear image in Java applications.
www.OnBarcode.com
Barcode Encoder In Java
Using Barcode creator for Java Control to generate, create Barcode image in Java applications.
www.OnBarcode.com
8.2 Getting familiar with the dynamic tags
PDF 417 Printer In Java
Using Barcode maker for Java Control to generate, create PDF-417 2d barcode image in Java applications.
www.OnBarcode.com
DataBar Creation In Java
Using Barcode creator for Java Control to generate, create GS1 DataBar Limited image in Java applications.
www.OnBarcode.com
iBATIS addresses the need for Dynamic SQL through a robust set of tags which are
UPCA Generation In Java
Using Barcode creation for Java Control to generate, create UPC-A Supplement 2 image in Java applications.
www.OnBarcode.com
USS Code 93, USS 93 Maker In Java
Using Barcode maker for Java Control to generate, create ANSI/AIM Code 93 image in Java applications.
www.OnBarcode.com
used to evaluate various conditions surrounding the parameter object that you pass into your mapped statement. It is important to know the full range of tags that exist and the various roles they play in producing correct SQL output. The following sections break the tags into five categories: <dynamic>, binary, unary, parameter, and <iterate>. Each grouping contains one or more related tags that share common traits. Before we examine each of these groupings, let s take a moment to note some common attributes and behaviors shared by all Dynamic SQL tags. All of the dynamic tags share the prepend, open, and close attributes. The open and close attributes function the same in each of the tags. They unconditionally place their values on either the beginning or the end of the resulting content of a tag. The prepend attribute functions the same in all of the tags except the <dynamic> tag. The <dynamic> tag will always prefix the prepend value when the processing of its body results in content. There is no way to prevent the value from being prefixed with the <dynamic> tag. Listing 8.2 shows some of the Dynamic SQL tags in action.
Generating PDF-417 2d Barcode In Java
Using Barcode drawer for Android Control to generate, create PDF 417 image in Android applications.
www.OnBarcode.com
Generating PDF417 In Visual C#
Using Barcode creation for .NET framework Control to generate, create PDF 417 image in .NET framework applications.
www.OnBarcode.com
Listing 8.2 Mock removeFirstPrepend example
Code 128 Code Set A Decoder In C#
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
DataMatrix Scanner In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
<dynamic prepend="WHERE "> <isNotEmpty property="y"> y=#y# </isNotEmpty>
Drawing EAN-13 Supplement 5 In None
Using Barcode encoder for Online Control to generate, create GTIN - 13 image in Online applications.
www.OnBarcode.com
Draw GS1 DataBar Limited In .NET Framework
Using Barcode generator for .NET framework Control to generate, create GS1 DataBar Stacked image in .NET applications.
www.OnBarcode.com
Opening <dynamic> tag
GS1 128 Creation In None
Using Barcode generator for Excel Control to generate, create UCC.EAN - 128 image in Microsoft Excel applications.
www.OnBarcode.com
UPC Symbol Encoder In Objective-C
Using Barcode creation for iPad Control to generate, create UPC-A image in iPad applications.
www.OnBarcode.com
Simple isNotEmpty tag
PDF-417 2d Barcode Decoder In VB.NET
Using Barcode reader for .NET framework Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
EAN / UCC - 13 Drawer In Java
Using Barcode printer for BIRT reports Control to generate, create EAN-13 image in BIRT applications.
www.OnBarcode.com
<isNotNull property="x" removeFirstPrepend="true" prepend="AND" open="(" close=")">
Generating 2D Barcode In .NET Framework
Using Barcode maker for VS .NET Control to generate, create Matrix image in .NET applications.
www.OnBarcode.com
Create UCC - 12 In .NET
Using Barcode printer for ASP.NET Control to generate, create USS-128 image in ASP.NET applications.
www.OnBarcode.com
More complex isNotEmpty tag
Getting familiar with the dynamic tags
<isNotEmpty property="x.a" prepend="OR"> a=#x.a# </isNotEmpty> <isNotEmpty property="x.b" prepend="OR"> a=#x.b# </isNotEmpty> <isNotEmpty property="x.c" prepend="OR"> a=#x.c# </isNotEmpty> </isNotNull> </dynamic>
Nested dynamic tag
At B, the opening <dynamic> tag implicitly enforces the remove first prepend functionality on child tags. If this <isNotEmpty> tag proves true C, then the implicit removeFirstPrepend will be met for the <dynamic> tag. Any following tags on the same level will have their prepend values prepended. This <isNotNull> tag D specifies the removeFirstPrepend attribute. The open and close attribute values will wrap the content produced in its body. At E, the first nested content-producing <isNotEmpty> tag will satisfy the removeFirstPrepend requirement. The first content-producing <isNotEmpty> tag will not have its OR prepend value prepended. This will produce correct SQL wrapped in the parentheses. The remove first prepend functionality is supported implicitly or explicitly in all of the tags. The <dynamic> tag supports it implicitly. All other tags support it explicitly with the removeFirstPrepend attribute. The remove first prepend functionality removes the first prepend of a child tag that produces content. If the first contentproducing child does not specify a prepend attribute, it will still count and all following content-producing child tags will have their prepend attribute prefixed to their content. The final piece of shared functionality to note is that all tags can be used independently of each other. This means that you do not have to nest all of your Dynamic SQL tags inside the <dynamic> tag. You could start with an <iterate> tag and nest <isNull> tags inside as easily as you could wrap them both with a <dynamic> tag. This functionality is provided because it is only necessary to use a <dynamic> tag when you want to use its open, close, or prepend value on its resulting content. Let s now analyze each tag category.
Using Dynamic SQL
8.2.1 The <dynamic> tag
The <dynamic> tag is a top-level only tag; this means that it cannot be nested. It is used to demarcate a section of Dynamic SQL. The tag is meant to provide a means for prefixing a common prepend, open, or close value to the resulting content of its body. The <dynamic> tag attributes are shown in table 8.1.
Table 8.1 <dynamic> tag attributes This value is used to prepend to the tag s resulting body content. The prepend value will not be prepended when the tag s resulting body content is empty. This value is used to prefix to the tag s resulting body content. The open value will not be prefixed if the tag s resulting body content is empty. The open value is prefixed before the prepend attribute s value is prefixed. For example, if prepend="WHEN" and open="(", then the resulting combined prefix would be "WHEN (". This value is used to append to the tag s resulting body content. The append value will not be appended if the tag s resulting body content is empty.
prepend (optional) open (optional)
close (optional)
Now that you have a reference for the attributes that can be used in the tag, listing 8.3 illustrates how to use the <dynamic> tag.
Copyright © OnBarcode.com . All rights reserved.