Hi,
I love your product.
I have a question regarding processing large data sets and your recommendation to use XPO data source for server side paging.
This looks like an attractive option for our company, although it may not be possible.
We allow end users to define there own table structures (consisting of fields) and store the structure as an xml document in a row in a SQL table (Called TableSchema).
We then provide a web based UI that allows the users to create read update and delete records based off of that structure. Each record created by a user is also stored as an xml document in a row in a SQL table (Called TableRecords)
We use DevExpress Grid to render these records. I dynamically create the grid based on the structure of the table defined by the user (in the TableSchema) table.
We have many many rows > 1 million. I am looking for ways to increase performance.
Here is my question…
It appears that you must create ORM objects which map the table to a class structure in order to use as an XPO data source.
Is there a way that I can dynamically build an ORM object at runtime so I can take advantage of Server side paging with XPO?
Thanks in advance
Mike McGrath
CTO
GroveSite
Ticket
Q330128
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Hi Mike,
It is possible to create a persistent object metadata at runtime. However, even dynamically declared entities should be mapped to individual database tables and columns. It is rather difficult to override the XPO architecture to store objects as packed XML data in one table instead. Although, it is possible to implement this functionality at the IObjectLayer level, we currently do not have examples. Besides, I am afraid you cannot take the advantage of using server mode in this scenario, because it is impossible to generate SQL queries with filters and sorting based on values stored inside XML data.
Thanks,
Michael.
Hi
Actually you can filter and sort on xml data types in SQL Server 2005
Example:
Table consists of Two columns
TableRecordID int
TableRecord xml data type
Here are the records in the table:
<TableRecord><FirstName>Jim</FirstName><LastName>Smith</LastName><State>AZ</State></TableRecord>
<TableRecord><FirstName>John</FirstName><LastName>Doe</LastName><State>TX</State></TableRecord>
<TableRecord><FirstName>Frank</FirstName><LastName>Smith</LastName><State>NY</State></TableRecord>
<TableRecord><FirstName>Frank</FirstName><LastName>Wilson</LastName><State>NY</State></TableRecord>
<TableRecord><FirstName>Bill</FirstName><LastName>Morrison</LastName><State>NE</State></TableRecord>
I can run the following query:
select TableRecord.value('(TableRecord/FirstName)[1]', 'nvarchar(max)') Fname
from TableRecordPOC
order by Fname
And it will order the items as follows:
Bill
Frank
Frank
Jim
John
In addition, I can filter xml data using the .Exist method of the xml data type. That being said, I should be able to use xml server side to sort, filter
If it is possible to implement this functionality at the IObjectLayer level and I am able to filter and sort xml data is it feasible to try this?
Hi Mike,
It's great that SQL Server allows you to sort and filter rows in this manner. Now, you should implement an object layer with a custom logic of storing and retrieving data. However, this is not a trivial task and we do not have examples of this functionality. We recommend that you review the SimpleObjectLayer class source code.
Thanks,
Michael.
Thanks Michael for your quick response. Have a good day
You can mark this question as answered and close
Mike
Hi Mike,
Please let us know if you need an additional assistance. We will be happy to help you.
Thanks,
Michael.