I have a grid that needs to show data from a large table. I don't want to load the whole table at once as that will be hard on memory. I'm aware that there is a virtual load on server mode but I'm loading from a local csv file and not using any sql server databases.
Are there any such methods for virtual loading to support custom data access objects so I can just grab data from my csv when the user scrolls down on the grid?
Any help much appreciated.
I don't believe any such thing exists. However, it's possible to roll your own by implementing the DevExpress.Data.IListServer interface. From what I've read on the subject, it doesn't appear to be a trivial task. These links might get you started.
Simple IListServer implementation
Does the XtraGrid support Virtual Load mode?
One alternative might be to import your csv data into a SQLite database. Then you could use a LinqServerModeSource as your data source. The following link provides details on how you might do that.
SQLite and Server Mode
Hope this helps.
Related
What would be the best approach to replace placeholders in a .docx document (Word 2010) with data coming from a MySQL database?
Can I just open the file using a server side language and do a string replace per each placeholder?
Is there any existing tool/library available?
Thanks
Disclosure: I work for Invantive.
Using Invantive Composition (http://www.invantive.com/products/invantive-composition) you can fill Word documents (letters, legal pleadings, insurancy policies) with data from a database (IBM DB2, Oracle, MySQL, Teradata and SQL Server) and then fully change the contents at will manually. It is intended for real Microsoft Word end-users (both the guys that make the template and the ones that use it) that access the databases through a central webservice and models with queries. Invantive Composition allows nested repeating groups of data and lay-out. Integrates into Microsoft Word using click once.
In the past, I personally have also been using JasperReports (http://community.jaspersoft.com/project/jasperreports-library) to generate letters using the RTF output target of JasperReports. It is free and works fine as long as you do not want to edit the output more than a few words and have Java/SQL development skills. Just as Invantive Composition it works fine for large numbers of different reports.
As long as you can control the environment completely, you can also consider using RTF as intermediate language (not for end-users, only real developers). Save document as RTF, replace parts of the text you need to be replacable, write a webservice that accepts the parameter and dumps back the resulting RTF. Takes some time to generate more complex tables (tables are obviously something invented by the human race after the RTF specification was written :-) This approach only works with very limited number of templates and when you have sufficient developer time available to get it up and running and stabilized.
As an independent reviewer, I have also seen cases where XML templates were used, but the results were not as good as with JasperReports.
**Disclosure: I lead the docx4j project **
There are heaps of existing tools/libraries available!
Yes, you can just do a string replace, but that is a brittle approach, since Word may have split the string across runs.
You can use MERGEFIELDs, or content control data binding.
docx4j supports all three approaches, but content control data binding is the most powerful.
ContentControlsMergeXML
MERGEFIELDs
VariableReplace
One thing to consider especially is "repeats". If you want say a row of a table in Word, for each matching row in your MySQL table, then you need a way to make this happen.
docx4j does this with a "repeat" content control around the table row; whichever solution you choose, I'd make sure up front that it can handle repeats.
If you want to use PHP the most complete available solution is PHPDocX.
You may check in the tutorial how to substitute placeholder variables by data coming from any data source (like a MySQL DB).
In particular, you may populate table rows with an indefinite number of entries and you may delete whole blocks of the Word document depending on the data fed to the application or build dynamical Word charts.
You may check the available DEMO for a simple but quite illustrative example (its inner workings are explained in the tutorial section).
You can use open Open XML SDK and replace your placeholders like this.
Disclosure: I lead the docxgenjs project
I think you shouldn't have to code everything by yourself, that's why I created a Mustache-like templating engine for docx
Demo:
http://javascript-ninja.fr/docxgenjs/examples/demo.html
Repo
https://github.com/edi9999/docxgenjs
It is JS-based and works client and server side.
Yes, you can use server side language to do it.
Check on apache POI.
http://poi.apache.org
Hello I read the above esp the comments and Ivantive looks impressive - but the solution I needed was much simpler. Use Selection.Range.InsertDatabase in Word to fetch records from an access database or excel spreadsheet or even just another word document. With the access solution you can choose the layout of the records to fetch and have it fetch just particular recordds based on a field (eg ID). Google the words above and it'll take you to MS guidance and an example VB script. Worked well in just a few mins. Now looking for VB script that asks the person what ID they want from the dbase and we're done.
it uses docx templates that have merge fields with java objects (the objects have the information you load from mysql or any other source). The xdoc report is an project for java language, the home page of the project is https://code.google.com/p/xdocreport/.
*Disclosure: I create the templ4docx project *
Hello
You can use templ4docx java library, which is on maven central repository, so you can just add it to your maven dependencies:
<dependency>
<groupId>pl.jsolve</groupId>
<artifactId>templ4docx</artifactId>
<version>2.0.0</version>
</dependency>
Example usage:
Docx docx = new Docx("E:\\template.docx");
Variables variables = new Variables();
variables.addTextVariable(new TextVariable("${firstName}", "John"));
variables.addTextVariable(new TextVariable("${lastName}", "Sky"));
docx.fillTemplate(variables);
docx.save("E:\\filledTemplate.docx");
More details you can find here: http://jsolve.github.io/java/templ4docx/
I have this issue with Core Data. I am creating a core-data-based application, for one of the tabs, to populate a UITableViewController. Basically, I have read somewhere that there is an issue with providing a pre-populated sqllite file to be used to load up the data. I created a pre-populated data file and at first had issues with Z_METADATA and other anomalies like that. If we are creating our own sqllite file, is there somethign we have to include, such as certain table names etc?
Note, I didnt create teh application with use core data for storage ticked at beginning, so im not sure if that makes a difference.
Doron, take a look and A Blog On Tech for a really great example of how to get what you are trying to do. Basically it's best to let Xcode create the base SQLite DB for you, copy it to your code directory, pre-populate your data there and then finally add it to the project through Xcode.
So while it is possible to work a Core Data application that you haven't created from the beginning in Xcode it is much easier to start from there.
It is very simple to retrieve data from a database and display it inside a DataGrid. However, what are the current practices to push the changes in the DataGrid back to the database? One can achieve this by inserting a lot of meta information, however, it is very tedious and not reusable.
There are libraries for persisting data across tiers, but as you say it isn't a simple task. LiveCycle DS ships with this capability when used in conjunction with Hibernate on the server. GraniteDS and Tide can perform a similar function, but for the most part you are left rolling your own. If you are using one of the many MVC frameworks available (I use PureMVC) it isn't difficult to create this type of functionality. Kind of tedious, but not difficult.
Which server side technology would you be using? You need to use HttpServer, WebService or RemoteObject's in Flex to push data to this server side app and that would then update the database.
Unless of course we're talking about a Flex/AIR Desktop App where connecting to databases directly is possible.
You can use RemoteObject, if you have a Java class on the server side that takes care of database connection and provides method to update database.
Just Create an ArrayCollection object from modified datagrid and pass it while doing a method call.
I think making changes to the database is the easiest part of this whole thing. The hardest part is making the DataGrid know exactly from which database table each cell comes from. If you're the one writing the query, then you can probably return a lot of meta-data, such as the private key and table name for each cell.
I'm looking for the best solution to allow our users to upload XLS spreadsheet so that they can be used to populate tables in our data warehouse (DW).
Our users are heavy Business Object (BO) users, and BO lets you export to XLS. When they have data in a spreadsheet that needs to be loaded to the DW, they need a process to upload the data in the XLS to the DW's db. As a result, we end up with many of these "interfaces" when I think that what we really need is a programmatic automated feed. Using Excel as a data source for inter-system feeds, in my gut, just seems like a bad idea to me.
Question #1: I'd like to see if you agree and why or why not.
OK, there is no swimming against that tide, so I now take as a given that XLS uploads are here to stay for us. Now I need to find the best solution. First, I'll explain what we do now and then what I don't like about it:
Via web pages, we provide empty XLS files (no rows) with a defined set of columns. Each file is intended to be used to update a different target dest table. In each spreadsheet is an "upload" button. Pushing the Upload button results in the macro in the spreadsheet serializing the contents of the file to CSV and FTPing the data to server folder. Periodically, a scheduler fires off an Informatica ETL job that uses the CSV file as input and loads the data into a custom XLS-specific staging table and then, if the records pass edits, into the appropriate target table. Any errors encountered are logged to an error table. For each XLS file uploaded, the data ends up in a separate staging and error table that is specific for the file.
Some of the things I don't like include about our process are:
1) The macro code in the XLS is too exposed, includes passwords for example, can be tampered with and there are issues ensuring that the users are using the latest XLS templates.
2) Business Rule edits are placed in the ETL program, where they should probably be, but because we would like to catch the errors ASAP, i.e, in the spreadsheet, edits are also added to the macro code. This results in duplication of business edits. I want these rules in one place and centrally controlled. IMHO, I think putting any macro code in the XLS introduces a maintenance issue, even calls to stored procedures (some of which we have) or calls to web services (we haven't yet tried to call .NET Web Services from XLS macros.)
3) Every XLS file upload template has its own process with distinct set of staging and error tables and a custom screen for reporting errors encountered. It seems like we need a more generalized re-usable solution.
Besides often getting data exported to XLS from BO, the users like also Excel because it is easier to edit a large number of records and less clunkier than editing individual records via a web interface.
This is the general direction that I am thinking:
First, I want the users to have the ease of editing of Excel with editing, but without including embedded macros in the spreadsheet. I experimented with Farpoint's Grid with Excel compatibility...
http://www.fpoint.com/netproducts/spreadweb/tour/excel.aspx
...and I found that it was quite easy to allow a user the ability to open up an XLS file that resides on their PC and have it open up in a browser and be able to easily access the data read from server-side .NET web code. Excel isn't running locally in their browser, but the functionality of Excel is reproduced, presumably through a lot of client sided scripting that I expect would be a real pain to duplicate myself. You can even cut and paste from a local spreadsheet into the web's spreadsheet. This sounds great, by biggest problem is cost. Our company is near death and won't allow us to purchase any new software.
Next, I want to identify the common components across all spreadsheet upload processing and come up with generic processing code. For example, I imagine a table which defines each of our spreadsheets and the format of each including the column names and data type definitions, perhaps in terms of their destination columns instead of hard coding. Based on this table template definition, I can generate XLS templates for download from this table definition. I can also perform simple generic edits to ensure that the data entered matches the table definition. And one common web page can be used to present the data and allow report data type mismatch errors and allow for the user to correct them. I would also define a common table for storing the data in a "staging" table, using a table with two columns, submission #, row num, name and value, perhaps. No more "custom everything" is the goal.
Next I need to decide where to put the business rules. My dept's mgt firmly believes that all loading of data should be done by Informatica ETL batch processes and therefore the rules/edits belong "in Informatica". I have zero experience with Informatica tools, I am more of a .NET guy. I am therefore unsure as to how these rules are implemented but I suspect that they are not reusable in the sense that they can be used by a .NET web page to validate a particular record against. You see, in some cases, when the user is not performing a bulk upload, they do have the ability to edit a specific record and I would like the same edits that were applied by the ETL bulk insert process to be applied to an individual update attempt to a single record via a web page. If the solution to write a single web service or stored procedure that can be called from either the web page doing an update of a single record or called thousands of times for each record in a bulk upload? The latter sounds inefficient.
Your thoughts on anything above would be very much welcomed.
From a cost perspective, the efforts you'll need to go through to re-create spreadsheet functionality on the web will exceed the cost of Farpoint or other controls. Even if you made $20 an hour, do you think you could complete a working product in under 2 weeks? I think you have the facts on your side when you discussed maintenance issues if you allow ETL functionality to exist in Excel - you have twice the amount of work to maintain the transformation rules. I think you need to convince management that in order to create a maintainable, robust solution you need some flexible utilities.
Farpoint is a good choice. There is also SpreadsheetGear that is a .Net engine that interprets Excel macros and can run on a web server. It has a Win32 control that allows you to create a WinForms solution with very Excel interface functionality. Last time I checked there was no web control for the product. It does an excellent job of providing Excel capability for processing large amounts of data.
Good luck. I think you will find a good solution since you seem to have a good grasp of the pro's and con's of all the different potential solutions.
I’m thinking through some database design concepts and believe that creating sample data simulating real-world volume of my application will help solidify some design decisions.
Does any anyone know of a tool to create sample data? I’m looking for something that’s database and platform neutral if possible (from MySQL to DB/2 and Windows to UNIX) so to test the design across different systems/architectures. I’m visioning some tool that you can:
point to a database table(s) (some configuration of the DSN, etc.)
introspect the fields and based on the field... (point-and-click or add some configuration)
have a means for expressing how to create sample data (MySQL Sample Data Creator is the kind of thing I vision but I think their'd be some more options like commit frequency so to create very large data sets... millions or billions of rows... don't think this tool would scale to the volume of data I want to create)
push a button and go (depending on your parameters, this may take a long time)
Any thoughts? Sure, I could write an app to do this but it seems so generic that I shouldn’t have to reinvent the wheel.
DBMonster is fine but I prefer databene benerator as I explained it in this answer to a similar question.
Something like DBMonster?
This page also has a listing of many DB data generators.
I cannot help you with MySQL or DB/2 but, in case anyone gets to this answer with a need for MS SQL Server, I can recommend the Data Generator from Red Gate.
Our test data generator, Datanamic DB Data Generator can do this for you. Works with MySQL. It uses default "generator settings" when loading your tables the first time. You can then "fine-tune" the fields and/or choose other "generators".