How to filter?

Christian Graus

Where is your data coming from ? It seems pretty straightforward to me, if you're using a database and want to filter from the DB. Just build a query on each keypress to return the data valid for that search.

Christian Graus - Microsoft MVP - C++ "I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

shyne7

yes im using a database and the search result would appear to the gridview...im having a combobox that would give the textbox choices on which to filter...but i dont know how to use the like clause in the select statement propely.. sql = "Select Supplier_Information.Supplier_ID,Supplier_Information.Supplier_Name,Supplier_Information.Address,Supplier_Information.Contact_No, Products.Product_ID, Products.Product_Name,Products.Product_Type, Products.Present_Price, Products.Past_Price from Supplier_Information, Products where Supplier_Information.Supplier_ID like '%s-%' " i have this code but it does not work properly...i want to come up with a textbox that would filter in every letter that they will type in the textbox.tnx

Pete OHanlon

Whoah - this is a really bad design. Don't attempt to do this because you are going to be hitting the database after every keypress. The more users you have, the more you are going to hit the database. How would you handle the case where the user enters some text and then starts to delete text? Thats the same data being queried many times. Please - rethink your design.

Deja View - the feeling that you've seen this post before.

shyne7

any suggestive design that i could make?may i know exacly what is the bad design that you are pertaining of...tnx

Pete OHanlon

I'm sorry, but I thought I'd made myself clear enough. Don't design a system where you are hitting the database so many times. Apart from anything else, you probably won't be able to retrieve the data and display it quickly enough if the user is a quick typist. As for the design - identify a more natural point for retrieving the data.

Deja View - the feeling that you've seen this post before.

shyne7

should i delete my combobox?or can i search any data on my database in my textbox without giving any choices for filtering

Pete OHanlon

This has stopped being a question about databases and become a question about an autofiltering combo box. The exact details of how to do this depends on whether you are using Win Forms or ASP.NET.

Deja View - the feeling that you've seen this post before.

shyne7

i using vb.net...actually i really want to know about filtering...hos to use the like clause for searching

rohitsrivastava

u want to filter so , u are writing the query. ok then in where clause fieldname like '" & textbox1.text & "%' u will get the result

shyne7

tnx...that helps...but i have two tables in one gridview...how could i view those in my gridview when i search for a data that is only in one of the tables

Colin Angus Mackay

shyne7 wrote:

i using vb.net

VB.NET is a language. The question was about frameworks. Which framework are you using? The ASP.NET framework or the WinForms framework (both of which are part of the larger .NET Framework)

shyne7 wrote:

hos to use the like clause for searching

WHERE SomeColumn LIKE '%'+@SomeSearchTerm+'%'

@SomeSearchTerm is passes as a parameter for security

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Colin Angus Mackay

rohitsrivastava wrote:

fieldname like '" & textbox1.text & "%'

NO NO NO NO!!!! Do NOT inject into SQL strings like this. I've been banging on about this for THREE years now! Doesn't anyone know about SQL Injection Attacks?! SQL Injection Attacks and Tips on How to Prevent Them[^]

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Pete OHanlon

Ah well - at least I did mention parameterized queries (albeit in another post):-D. Don't worry Colin - some of the more professional members of the site have read/taken in your message. Perhaps your technical test should include a query that's wide open for Sql Injection and then ask candidates if they can tell you what's wrong with it.

Deja View - the feeling that you've seen this post before.