A calculated value is a read only property that is calculated using sql expressions. In this example we are building a blog application that has posts and comments. First we have a post entity. I have stripped these down for this example so we can look at the root of the issue. component persistent="true" extends="BaseEntity" { property name="title"; property name="body" ormtype="text"; property name="alias"; property name="allowComments" type="boolean"; property name="featured" type="boolean"; property name="released" type="boolean"; property name="views" ormtype="integer"; property name="comments" fieldtype="one-to-many" cfc="Comment" fkcolumn="post_id" singularname="comment" inverse="true"; } And then we have a comment entity. component persistent="true" extends="BaseEntity" { property name="name"; property name="email"; property name="url"; property name="body"; property name="post" fieldtype="many-to-one" cfc="Post" fkcolumn="post_id"; }

So far this is pretty basic stuff, nothing really special going on here. Now we need to grab a record from our database and display it, easy enough. <cfset post = entityLoadByPK("Post",1)> There is a major problem here with our display though. How would we get a count of the number of comments for this post? You could count the array of comments. <cfset commentCount = arrayLen(post.getComments())> While this would work your going to have to do this 2x on the post display page now. One time for the comment count and then a 2nd time to display the comments. In a post where there is only 1 or 2 comments this will not be a big issue but you can imagine the trouble this would cause with a large number of comments. A better solution to this problem is to use a calculated value. We can actually create this commentCount as a property of our post entity. component persistent="true" extends="BaseEntity" { property name="title"; property name="body" ormtype="text"; property name="alias"; property name="allowComments" type="boolean"; property name="featured" type="boolean"; property name="released" type="boolean"; property name="views" ormtype="integer"; property name="commentCount" formula="select count(c.id) from Comment c where c.post_id = id"; property name="comments" fieldtype="one-to-many" cfc="Comment" fkcolumn="post_id" singularname="comment" inverse="true"; } All we are doing here using SQL to the count. The id of the Post Entity is id (comes from the base Entity) so we can do a lookup in the comment table based on post_id being equal to id. Now if we want to output the count all we have to do is. <cfset commentCount = post.getCommentCount()>

This entry was posted on September 7, 2010 at 9:13 AM and has received 3421 views. Comments 17 | Print this entry.

This is a going to be a real short post but I think its a great little time saver. In ColdFusion 9.0.1 they added a second argument for the entityNew function. Now you can pass in a structure of properties and the setters will be called when the entity is instantiated. So before we had to write code that looked like this. <cfset user = entityNew("User")> <cfset user.setFirst("Dan")> <cfset user.setLast("Vega")> <cfset user.setSex("M")> And now we can write code that looks like this. user = entityNew("User",{first="Dan",last="Vega",sex="M"});

This entry was posted on August 8, 2010 at 11:48 PM and has received 2594 views. Comments 2 | Print this entry.

One way to debug Hibernate is to log the generated sql, another way is by enabling live statistics. By default ColdFusion has live statistics disabled and for good reason. This is not something you want running in production and its only meant for development. The easiest way to get statistics out of the Hibernate engine at runtime is the Session Factory. Fortunately for us ColdFusion has exposed this to us by using the ormGetSessionFactory() method.

If you run the following code you will see all of the different statistics methods exposed to you. stats = ormGetSessionFactory().getStatistics(); writeDump(stats);

There are statistics for things like

• Global Statistics
• Entity Statistics for a particular entity
• Collection Statistics for a particular collection role
• Query Statistics for SQL & HQL queries
• Second Level Cache Statistics for detail runtime information about a particular region in the optional second-level cache

If you try and call any of these methods right out of the gate they are not going to work. If you remember I said earlier that statistics are not enabled by default, but we can enable them pretty easily. stats = ormGetSessionFactory().getStatistics(); stats.setStatisticsEnabled(true); Now when you call any of the stats methods we will start to see some data. There is also a continent method to find out if they are enabled. stats = ormGetSessionFactory().getStatistics(); stats.isStatisticsEnabled();

Finally we could take this and add some debugging output to application by using the on request end method in our application. The hibernate_stats.cfm could have some output with any or all of the statistics methods. public any function onRequestEnd(){ var stats = ormGetSessionFactory().getStatistics(); stats.setStatisticsEnabled(true); if(stats.isStatisticsEnabled()){ include "hibernate_stats.cfm"; } }

This entry was posted on August 8, 2010 at 6:21 PM and has received 3190 views. Comments 9 | Print this entry.

In a perfect world of software development where a database is involved the naming conventions for tables and columns are standard. As you are aware that is not always the case. Sometimes we deal with really long or unconventional naming strategies. Fortunately for us hibernate has a way of dealing with this and ColdFusion, like everything else it does has made this really for us to use.

Let's pretend for our demo here that we are doing some work for ABC Company and that have this weird naming strategy where all of there table names are prefixed with tbl_ and all of their column names are prefixed with col_. tbl_Person col_firstname col_lastname col_email col_dob col_sex I think you get the idea. If we were to create an entity based off of this table we would end up writing code that looked like this. person = new Person(); person.setCol_FirstName("Dan"); person.setCol_LastName("Vega"); person.setCol_Sex("M");

Continue Reading >>

This entry was posted on August 7, 2010 at 7:35 PM and has received 3175 views. Comments 3 | Print this entry.

Working on a project today I came across a strange issue so I thought I would get everyones opinion on it. I am not really sure if its something I am doing wrong, a bug or maybe I am just missing something. In this application I have event handling turned on. this.ormenabled = "true"; this.datasource = "*********"; this.ormsettings = { cfclocation = "models", eventhandling = true, eventhandler = "cfc.com.*******.********.events.eventHandler", dbcreate = "dropcreate", sqlscript = "install/derby.sql" };

So for nothing special and up until this point everything has been working fine. Today I am adding some ajax via everyone's favorite framework (jQuery of course) and I came across something. This is my ajax call to my remote method. $.ajax({ url: "services/User.cfc", data: {method:"getByRole",role:roleid,returnformat:"json"}, success: function(data){ console.log(data); } }); And my remote method that does a join to pull all users who have a role id equal to the argument passed. remote any function getByRole(Numeric role){ var users = ormExecuteQuery("select u from User as u inner join u.roles as r where r.roleid = ?",[arguments.role]); return users; }

If you were to turn event handling off this works fine but with it on I am seeing the following error.

coldfusion.runtime.TemplateProxy$InvalidRemoteAccessException: The method 'preLoad' in component D:\websites\extranetsteriscom\cfc\com\*****\*****\events\EventHandler.cfc cannot be accessed remotely.

Now in my event handler I have preLoad defined (because you have to when you implement another component) but it's not doing anything. Am I to believe that If I use event handling in my application I can't use ORM for any remote functions? I can certainly get down and write some sql but thats no fun :) Anyways, just thought I would share this and get your thoughts.

This entry was posted on March 4, 2010 at 12:01 PM and has received 2275 views. Comments 21 | Print this entry. Download attachment.