Hi people. I have problem. I have database with 500k records. Each record store latitude, longitude, specie of animal,date of observation. I must draw grid(15x10) above mapkit view, that show the concentration of specie in this grid cell. Each cell is 32x32 box. If I calculate in run-time it is very slow. Have somebody idea how to cache...
Our application uses an Oracle 10g database where several primary keys are exposed to the end user. Productcodes and such. Unfortunately it's to late to do anything with this, as there are tons of reports and custom scripts out there that we do not have control over. We can't redefine the primary keys or mess up the database structure. ...
Nowadays, "Prepared statements" seem to be the only way anyone recommends sending queries to a database. I even see recommendations to use prepared statements for stored procs. However, do to the extra query prepared statements require - and the short time they last - I'm persuaded that they are only useful for a line of INSERT/UPDATE qu...
Our Mnesia DB is running slowly and we think it should be somewhat faster. So we need to profile it and work out what is happening. There are a number of options that suggest themselves: run fprof and see where the time is going run cprof and see which functions are called a lot However these are both fairly standard performance ...
I am going to be creating a work order system with three roles The "client" - The client can request projects to be completed by the worker. The project must be selected from a list of templates and various sub options all referred to as a campaign (campaign types come and go throughout the year) The worker - The worker must be able to...
If you had two databases, that had two tables between them that would normally implement a one to one (or many to many) constraint but cannot since they are separate databases, how would you validate this relationship in an application or test? Is there a simple way to do this? For example, a tool or technique that can, given a constrai...
I have a model "Messages" which i use to store messages throughout the site. These are messages in discussions, private messages and probably chat. They are all stored in 1 table. I wonder if it will be faster if i spread messages among several models and tables. 1 for chat, one for discussions and so on. So should i keep all message...
Hello, I wonder to know if someone can help to understand if I'm doing well using a single table with wiki content for multiple subjects, so: TABLE wiki ==> wiki_id wiki_content wiki_language wiki_user_id TABLE houses house_id house_name house_year house_location ==> wiki_id TABLE architec...
How do I connect my local client application with the database on the server? I am using Delphi and MySQL. ...
Hi, I would like execute a query like this one in symfony using the Propel ORM: UPDATE ADS SET HITS=HITS+1 WHERE ID=10; I know that Propel API can let me set a previously fixed value for a column of a given record, but I definitely don't want to retrieve the column value first before issuing an update query since there are concurrent...
Why is using a parameterized query to insert data into a table: string queryString = "insert into product(id, name) values (@id, @name)"; faster than appending the values to the query string: string queryString = "insert into product(id, name) values (" + _id + ", " + _name + ")"; ? When I use the command in a loop to insert 10K r...
I need to compute a list of table names in a given database (MDB format), which have certain format (for example which containt DateTime field "Date Applied"). How can I do it? Note: I am using Delphi 7, ADO components, Microsoft JET 4.0 to connect to MDB type Database. ...
I've been reading a lot about Relational Databases using many JOIN statements on every SELECT. However, I've been wondering if there's any performance problem on the long run when abusing this method. For example, lets say we have a users table. I would usually add the "most used" data, instead of doing any extra JOINs. When I say the "...
My problem: I got a MySQL database that stores a great amount of meteorological data in chronological order (New data are inserted every 10 min). Unfortunately there have been several blackouts and hence certain rows are missing. I recently managed to obtain certain backup-files from the weather station and now I want to use these to fi...
This is the question about JDBC. I have next task. I'm iterating through rows from table A and for some current row I want to execute some query against table B in context of current row from A. For example, if I have some query like SELECT B.description FROM A LEFT JOIN B ON A.ID = B.refId then I want to get all results where B.refI...
Hello, I have in my database a table Articles with Article Name and Article Tags. Article tags is a string column with tags in it like this: "people, life, president". Every article is tagged in this fashion. Now i would like to get 10 most popular tags for whole population of articles. How to do this? ...
One of the benefits of prepared statements, (really the only major one) is that SQL commands/triggers are sent in one request - and the user-data (or whatever you provide) is sent in another transfer. This transfer of the user-data (i.e. for an INSERT) is supposed to be in binary form so that PHP (and then the DB server) don't waste time...
Hi, I'm looking to know how to calculate shipping cost for sending pages to remote sites of a distributed database. The explanation I have is: "Tuples are shipped in units of one page by waiting for a page to be filled before sending a message from processor i to processor j" If it helps, each processor have 100 buffer pages of 4000 b...
I've created a user-maintained MQT (Materialized Query Table) in DB2 9.7 (not yet fixpack 1). It's a simple grouping of the main fact table. But my queries aren't being rewritten to hit it. Here's what I've tried: Created the MQT with ENABLE QUERY OPTIMIZATION and MAINTAINED BY USER characteristics Also included REFRESH DEFERRED & D...
How do you insert a group by count result into a table? I'm trying to insert a list of names with counts for each. Thanks!! ...