Oss questions

Oss questions

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  what is thedifference between sql and mysql SQL means "structured query language" which is the syntax of commands you send to database. MYSQL is the database program which accepts the those commands and gives out the data. what is the difference between echo and print in php? When outputting something with PHP, we use print or echo functions. what exactly is the difference between those functions? difference between superkey candidate and primary keys Super key is the set of attributes in a table that can uniquely identifies a database tuple(row or record). Candidate key is the minimal set of super key that can uniquely identifies a database record. Primary key is one of the candidate keys. you can select any candidate k Advantages of MySQL 5.1 compared to MySQL 5 Please find the following features that has been added to the MySQL version 5.1. 1. Partitioning 2. Row Based Replication 3. Plugin API 4. Server log table 5. Upgrade program 6. MySQL Cluster 7. Backup of tablespaces 8. Improvements to INFORMATION_SCHEMA 9. XML functio What is AJAX? Asynchronous JavaScript and XML, is a web development technique for creating interactive web applications. The intent is to make web pages feel more responsive by exchanging small amounts of data with the server behind the scenes, so that the entire w What is the difference between constructors in PHP4 & PHP5? Constructors - PHP4 Constructors are functions in a class that are automatically called when you create a new instance of a class with new. A function becomes a constructor, when it has the same name as the class. If a class has no constructor, the constructor of the base cla What is meant by Exceptional Handling? Exceptions PHP 5 has an exception model similar to that of other programming languages. An exception can be thrown, try and caught within PHP. A Try block must include at least one catch block. Multiple catch blocks can be used to catch different classtypes; execution will co What is meant by Virtual hosting? Virtual hosting HTTP includes the concept of virtual hosting, where a single HTTP server can represent multiple hosts at the same IP address. A DNS server can allocate several different host names to the same IP address. When an HTTP client ma What is meant by Session Clustering? The Session Manager session support allows multiple server instances to share a common pool of sessions, known as a session cluster Session clustering setting up methods : How does Database handle Sessions? As you should be aware the HTTP protocol, as used for serving web pages, is completely stateless. This means that after the server has received a request, processed it and sent a response, the process which dealt with that request dies. Anything that
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  What is thedifference between include and include_once? Include() The include() statement includes and evaluates the specified file. This also applies to require(). The two constructs are identical in every way except how they handle failure. include() produces a Warning while require() results in a Fatal Error. What are static methods? Static Keyword Declaring class members or methods as static makes them accessible without needing an instantiation of the class. A member declared as static can not be accessed with an instantiated class object (though a static method can). The static declar What is Phishing? In computing, phishing is a form of criminal activity using social engineering techniques. It is characterized by attempts to fraudulently acquire sensitive information, such as passwords and credit card details, by masquerading as a trustworthy person or business in an ap Do you know about Cross site Scripting ? Cross-site scripting (XSS) is a security exploit in which the attacker inserts malicious coding into an link that appears to be from a trustworthy What is session hijacking? Session hijacking, also known as TCP session hijacking, is a method of taking over a Web user session by surreptitiously obtaining the session ID and masquerading as the authorized user. Once the user's session ID has been accessed (through session prediction), the attacker and a range of logical and loop operators to allow adaptability within of the template. What is Model-view-controller (MVC)? Model-view-controller (MVC) is a design pattern used in software engineering. In complex computer applications that present lots of data to the user, one often wishes to separate data (model) and user interface (view) concerns, so that changes to the user interface do not What is the difference between mysql_fetch_object and mysql_fetch_array? Returns an object with properties that correspond to the fetched row and moves the internal data pointer ahead. mysql_fetch_object() example What is the difference between GET and POST methods in form submitting? Give the cases where we can use GET and POST methods? The main difference between GET and POST is how the form data is passing. Both are used for passing form field values. All the values which is submitted by the GET method will be appended to the URL. Where as POST method send the data with out appending the URL( What is the difference between strstr() and stristr()? Strstr -- Find first occurrence of a string strstr() example stristr -- Case-insensitive strstr() stristr() example What is meant by PEAR in php?
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  PEAR PHP Extensionand Application Repository PEAR is the next revolution in PHP. This repository is bringing higher level programming to PHP. PEAR is a framework and distribution system for reusable PHP components. It eases installation by bringing an automated wiz What is the difference between char and varchar data types? Set char to occupy n bytes and it will take n bytes even if u r storing avalue of n-m bytes Set varchar to occupy n bytes and it will take only the required space and will not use the n bytes eg. name char(10) will waste 5 bytes if we store ‘testname&rsqu What is the functionality of md5 function in PHP? Calculate the md5 hash of a string. The hash is a 32-character hexadecimal number. What is the difference between GROUP BY and ORDER BY in MySQL? ORDER BY [col1],[col2],…,[coln]; Tels DBMS according to what columns it should sort the result. If two rows will hawe the same value in col1 What is MIME? MIME is Multipurpose Internet Mail Extensions is an internet standard for the format of e-mail. Howewer browsers also uses MIME standart to transm Is it possible to pass data from JavaScript to PHP? A. Yes, but not without sending another HTTP request. B. Yes, because PHP executes before JavaScript. C. No, because JavaScript is ser what is session_start() ? When a user first encounters a page in your application that call ssession start(),a sessionis created for the user.PHP generates a random session identifier to identify the user,and then it sends a set- Cookieheader to the client.By default,the name of this cookie is PHPSE How many values can the SET function of MySQL take? MySQL SET function can take zero or more values, but at the maximum it can take 64 values. what is database testing and what we test in database testing? Database testing basically include the following. 1)Data validity testing. 2)Data Integritity testing 3)Performance related to data base. 4)Testing of Procedure,triggers and functions. for doing data validity testing you should be good in SQL q What is PHP? PHP: Hypertext Preprocessor, an open source, server-side, HTML embedded scripting language used to create dynamic Web pages. What can PHP do? Anything. PHP is mainly focused on server-side scripting, so you can do anything any other CGI program can do, such as coll Why should we use Object oriented concepts in php ? 1. Object oriented PHP code is much more reusable because by its' very nature, it is modular. 2. Object oriented PHP is easier to update. Again, because PHP code is organised into objects. 3.
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  Object oriented PHPmakes team programming much easier PHP offers an extremely simple solution to dynamic caching in the form of output buffering. what are the most common caching policy approaches ? 1)Time triggered caching (expiry timestamp). 2)Content change triggered caching (sensitive content has changed, so cache must be updated). 3)Manually triggered caching (man What Are PHP Arrays? PHP arrays are associative arrays with a little extra machinery thrown in. The associative part means that arrays store element values in association with key values rather than in a strict linear index order. (If y Are php strings immutable ? PHP strings can be changed, but the most common practice seems to be to treat strings as immutable.Strings can be changed by treating them as character arrays and assigning directly into them, like this: What is Memcache? Memcache is a technology which caches objects in memory where your web application can get to them really fast. It is used by sites such as Digg.com, Facebook.com and NowPublic.com and is widely recognized as an essential ingredient in scaling any LAMP