Read and write dat file in php

recently i've used Maxmind geoip to locate country & city based on the ip. It has huge content inside the dat files. but retrieving of those records happens within a seconds. so i'm so curious to learn and use the technology in php.

First i've seen some video files are using this .dat extension files and now text information. so what is .dat extension actually? is it possible to read and write in php.

Thanks开发者_运维百科!

For what I know, dat extension means a generic file in which you could write what you need, in the format you please.
I mean, in every file you could do that, but generally if you find an xml file you assume that inside you find xml formatted text; on the contrary dat files are not recognized as something you can decode with a specific software if you don't know who and how wrote it.

The files will most likely be in a custom format that they developed; if it's open source you could reimplement it in PHP (if it isn't already written in PHP), or maybe access the data through an API.

The speed will come from the fact that it'll be indexed in some way, or it's like "for every record move 100 bytes further into the file".

There's a lot of questions here.

First, the file is a database - it stores data. There are lots of database models - relational, herarchical, object-oriented, vector, hypercube, keystore....there are implementations of all these available off the shelf.

Some databases are more apposite to managing particular data structures than others. Geospatial data is a common specialization - so much so that a lot of other database types will provide vector functionality (e.g. mysql and postgresql which are relational databases).

For most database systems, the application using the services of the database does not access the data file directly - instead access is mediated via another process - this is particularly relevant for PHP since it typically runs as multiple independent processes with no sophisticated file locking functionality.

So if you were looking to implement IP to geography info yourself, I'd recommend sticking to a relational database or a nosql keystore (you don't need the geospatial stuff for forward lookups).

But do bear in mind that IP to geo lookup data is not nearly as accurate/precise as the peolpe selling the products would have you believe. If your objective is to get accurate position information about your users, the HTML5 geolocation API provides much better data - the problem is availability of the functionality on user's browsers.