I've been working with RedQueryBuilder primarily as a tool for allowing users to place constraints on a single table query. However, I need to add constraints to a more generic visual query and was wondering how to go about this using RQB.
You can see a prototype of my visual query builder here:
http://ordsvqd.bitballoon.com/
I could add a constraints table for all the selected columns, rather like MS Access, or use RQB. However, I'm not sure where to start for RQB - would I need multiple instances of RQB widgets, one per table?
I'd have thought one instance of RQB. You can tell RQB what SQL to start with and it can handle joins.
Your prototype does selection of columns which RQB does not try and do.
Might be "interesting" in that RQB might want to add/remove a table from the query as your prototype does. As a user I think that would be quite cool.
Looks like a good project. When and up and running maybe raise an issue with RQB to get the documentation (at least) to link to your project?
Related
I currently have a REST endpoint with basic CRUD operations for a sqlite database.
But my application updates whole tables at a time (with a "save" button)
My current idea/solution is to query the data first, compare the data, and update only the "rows" that changed.
The solution is a bit complex because there are several different types of changes that can be done:
Add row
Remove row
Row content changed (similar to content moving up or down)
Is there a simpler solution?
The most simplest solution is a bit dirty. (Delete table, create table and add each row back)
The solution is a bit complex because there are several different types of changes that can be done:
Add row
Remove row
Row content changed (similar to content moving up or down)
Is there a simpler solution?
The simple answer is
Yes, you are correct.
That is exactly how you do it.
There is literally no easy way to do this.
Be aware that, for example, Firebase entirely exists to do this.
Firebase is worth billions, is far from perfect, and was created by the smartest minds around. It literally exists to do exactly what you ask.
Again there is literally no easy solution to what you ask!
Some general reading:
One of the handful of decent articles on this:
https://www.objc.io/issues/10-syncing-data/data-synchronization/
Secondly you will want to familiarize yourself with Firebase, since, a normal part of computing now is either using baas sync solutions (eg Firebase, usually some noSql solution), or indeed doing it by hand.
http://firebase.google.com/docs/ios/setup/
(I don't especially recommend Firebase, but you have to know how to use it in as much as you have to know how to do regex and you have to know how to write sql calls.)
Finally you can't make realistic iOS apps without Core Data,
https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/CoreData/index.html
By no means does core data solve the problem you describe, but, realistically you will use it while you solve the problem conceptually.
You may enjoy realm,
https://realm.io
which again is - precisely - a solution to the problem you describe. (Which is basically the basic problem in typical modern app development.) As with FBase, even if you don't like it or decide not to go with it on a particular project, one needs to be familiar with it.
I am trying to use the embedded reporting tools in VS2012. I never used them before.
The report wizard force the user to select a table and I do not see any feature that allows to add or select more than one table in the same report.
I see that there are not so many Q&A on this topic and also I have not found any decent tutorial rather then very simple samples with two columns, but lets give it some time.
Is there a way to get data from different tables of the same DB into the same report?
Your best bet is to create a SQL view and then use that. The wizard does however give you the option to choose more than one table when you create a new dataset.
I am wondering about the model-first approach. I wish to design a new database using the model designer in VS2012. The new features of the model designer such as coloring and splitting up model sections are wonderful. Hopefully there will be purpose for using the model designer beyond initially creating a new database.
I would like to perform the following steps...
using the model designer, visually design and push the model to create the initial database and a table
add data to the table
make a change to the table in the model designer (e.g. add a field)
push the changes to the database (i.e. update the database)
NOT LOSE MY DATA FROM STEP 2. Also, just to clear any confusion... did I mention that I DON'T WISH TO LOSE THE DATA?
Please, please tell me this obvious need (i.e. the need to evolve the the tables and their fields without losing data, starting from scratch) has not been overlooked in iteration FIVE of EF.
This page on EF (http://msdn.microsoft.com/en-us/data/ee712907.aspx) makes things sound that the developer has equal choices between coding first and modeling first. To me, the intro video on the page creates a similar impression.
It would be nice if there were a simple menu option or better yet just a way to establish "automatic pushes to DB" upon changes to the model. That way whenever changes are made and the SAVE button is clicked, a dialog could appear "Update database?".
I see that using code-first there is a migrations option. I cannot seem to find the same for model-first. And I don't understand why this wouldn't be possible... after all the code that I would have written in code-first does indeed exist - it was created by the model-first code generation.
I'm keeping my fingers crossed in hopes someone will have a simple solution, perhaps something I've just overlooked and all this rambling/venting is in vain. :-)
You really have to use code-first if you want to modify your database when the model changes. Even then it's not some magical automated process but you'll have to script the changes.
With model first your best option is to generate a new database each time and create a change script (DDL) by using a tool like Redgate's SQL Compare or a Visual Studio Sql Server Database Project.
I'd like to add that it is virtually impossible to synchronize a database automatically with a model. Some changes require manual intervention, e.g. removing a field and adding another field cannot be distinguished from renaming/retyping a field. Some changed can easily be done in a model, but would require a table rebuild script in Sql Server (e.g. changing field order), or a combination of modified content and structure (e.g. making a field not null, adding a foreign key).
At the moment the only thing to do is:
Copy your database file... (backup)
Allow EF to recreate the database according to model
Per table copy-paste your records from backup to your new db.
This is not that easy as you need to copy paste in a specific order because of relations and it will only be good for minor changes such as adding columns and new tables or removing scalar columns or removing tables.
But I am certain that this is the begining of a correct approach to deal with the problem which later on can be automated by writing a more generic migration app between two databases which share same table names and relations.
Deeper problems begin when the relations are not the same / table names changed / column names changed.
I'm in a VERY difficult problem.
I have a Microsoft Access Data Base, but it was made in the most chaotic way possible. The DB has like 150+ tables, Only uses like 50% of the tables. The relations are almost random. But, somehow, it delivers some information.
I need to get a particular component of the DB, but is so tangled that I can not manage to get into the table that creates that value. I revised every table, one by one, and found nothing.
I used mdbtools for Linux to try to inspect with more details the DB. But unfortunately has not been developed in years, and it closes every time. Maybe because the DB is "big" ? -700 mg-
I'm wondering: is there a way to see all the relations the arrives to the particular value I'm looking? Or to decompile the DB? I have no idea in which language it was made. I'm suspecting that it was made in Visual, just because is rather crappy.
Well, waiting for some help.
I would suggest using (still) MS Access for this. But, if relationships look messy on the diagram, you can query one of the system tables (MSysRelationships) directly to get ALL the relationships you need (e.g. for particular table etc.):
To unhide system tables in early versions of Access (97-2003), follow the instructions here:
For Access 2007, do the following:
I'm evaluating SubSonic 3.0 for use in our business as a replacement for our POCO objects. I'm new to SubSonic, literally installing it yesterday. I've gotten to the point where I can connect to one database using the 3.0 LINQ T4 Templates, and have been wooed by the promise of being able to connect to multiple databases in one application using SubSonic.
My issue is I can't find any documentation on how to use the T4 Templates with multiple databases (e.g. adding another connection string, setting up the Settings.ttinclude etc).
I've searched Google and Stackoverflow for an answer to see how this would be done or if its even possible. Any help would be appreciated.
So I seemed to be able to make it work by adding another connectionString to the web.config, and then adding a 2nd set of templates for that connectionString, it works, but it doesn't seem 'clean' or even really that DRY to me.
It also seems that I could do almost the same thing with the .NET Built in LINQ by adding multiple .dbml files.
Can anyone give me some reasoning at this point why we shouldn't just use the built in LINQ support over a 3rd party ORM like SubSonic?
Cross posting from the subsonic mailing list:
Oh yeah I do this all the time, the trick is two copies of the templates(easy) or editing the templates to iterate over two sets of tables(harder). In the second settings.tt change the name of the connection string to reflect the other database. You might also want to change the namespace so that you don't have conflicts where table names are the same. It seems hacky but I don't think it is because it allows you to make changes to the templates for each database independently.
If you really want only one set of templates the easiest way to go about it is to edit SQLServer.tt (or your choice of database) and override how LoadTables works such that it will accept a list of connections rather than a single one. I have to say this is a pain and it is going to be much harder than having 2 copies of the files.
(In reply to your answer of your question)
Can anyone give me some reasoning at this point why I shouldn't just use the built in LINQ over a 3rd party ORM like SubSonic?
On immediate thought: SubSonic supports more than just Microsoft Sql Server.