FAQ Database Discussion Community

How does trec_eval calculates Mean Average Precision (MAP)?

I'm using TREC_EVAL to evaluate a search engine. I'd like to know how it calculates the Mean Average Precision (MAP). I'm sure it doesn't calculate a simple average of the average precisions (AP). It seems a weighted arithmetic but I can't understand which weights are used.

Questions about CACM collection

I'm using CACM document collection. I tried to search more information on this collection online but unfortunately I didn't find what I was looking for. If I've understood correctly, this collection contains documents from a paper journal. As far as this is concerned, I don't understand why every document always...

Count rows of data and display in view ASP.net MVC

All i'm trying to do is count how many bookings have requested wheelchair access not sure with the best way.... using (var context = new TalyllynContext()) { var count = context.Bookings.SqlQuery(" SELECT * FROM dbo.Booking Where Wheelchair_Access = 'true' ").Count(); } ViewBag.Count = count; This is what i want to...

What is the best way to retrieve table from MySQL using PHP?

I just have SELECT query which returns table. I don't like to type this query into PHP scripts. I want to create functions and procedures to retrieve data so I just call from PHP, and so it works properly with UPDATE, DELETE statements. But I can't return table! So what...

Unable to retrieve createdAt values from Parse objects

I cannot get the createdAt value from Parse for each object.And I dont want to have to save an additional timestamp as a String when the data is sitting right there. This is the list of what i was doing.I hope someone who can help ---------------------------------------------------------------------- var followArray = [String]()...

How big a factor is blob size on retrieval time in Azure Storage?

I am storing text files in Azure Blob Storage. The files will be on the order of 1MB, but I could theoretically reduce that size by perhaps 30% at the cost of significantly increasing my application logic complexity. I'm leaning toward just using the simpler but larger files. However, I...

Android parse value from .sqlite file

How to parse value from .sqlite file, i n my sqlite file there are more than 1000 records now i need to retrieve all the values and need to show that in a listview, i have saved that file in to my asset folder, is there any way to do...

How to retrieve data from sql by List<> instead of data table?

How to retrieve data from Database by ( List<> ) instead of data table? How can I do this?...

How to get a parameter as a result of a search condition from a XML-File? [duplicate]

This question already has an answer here: How to read XML using XPath in Java 4 answers Im getting via Webservice an XML File and now I want just to get certain data out of it by finding a certain match in the same tag: For example: < Person...