While creating a table a particular column / field can be made autoincrement as : The value of an autoincrement column increments automatically with every insert and doesnt need to be specified in the insert command. It is 1 + the value of the same field in the previous row. Now data can be inserted… Read More »
To go back to the previous page the superglobal variable $_SERVER can be used. $_SERVER[‘HTTP_REFERER’] has the link to the previous page. So to redirect simply : Last Updated On : 1st July 2009
The numerical system used in India differs from the Western system in terms of the placement of the thousands separator. Example : Number -> 1000000 Indian System -> 10,00,000 (Ten Lakh) Western System -> 1,000,000 (1 Million) While echoing numbers in PHP it is possible to format numbers with such separators using functions like number_format…. Read More »
bit.ly is a simple url shortner which has an api , which can be called from within php to shorten links. Code : The above function can be used to shorten a big url , as : The function needs an api key. To get your api key simply register at bit.ly then go to… Read More »
Raw tcp sockets in C Raw sockets can be used to construct a packet manually inside an application. In normal sockets when any data is send over the network, the kernel of the operating system adds some headers to it like IP header and TCP header. So an application only needs to take care of… Read More »
TCP/IP 3-way handshake is done to establish a connection between a client and a server. The process is : 1. Client –SYN Packet–> Server 2. Server –SYN/ACK Packet –> Client 3. Client –ACK Packet –> Server The above 3 steps are followed to establish a connection between source and destination. SYN Flood DOS attacks involves… Read More »
Ip to Location Many applications need to get information about the geographical location of the user/visitor on their websites. This can be done in many ways. There are online services like ipinfodb and geoio that provide web based api to get the geolocation information about a given ip address. Services like Maxmind geoip provide free… Read More »
Parsing dates Most php applications need to parse dates and convert them to timestamps for example. Parsing is also necessary to convert the date into a more standard format like yyyy-mm-dd which can be stored in a database like mysql. Mysql database stores dates in the format yyyy-mm-dd like 2009-04-15. However humans are more used… Read More »
This is a simple class that evolved out of the php code I wrote so far. It has the following functions : 1. dbms() – The constructor to do the initialisation like connecting to the database etc. 2. query($query) – The method to take a sql string and perform the query. 3. close() – Close… Read More »
In a previous post we learnt how to inside php. In this example the same zip file would be used to restore the database. Code Last Updated On : 1st May 2009