Ans: A network is a set of devices connected by physical media links. A network is recursively is a connection of two or more nodes by a physical link or two or more networks connected by one or more nodes.
Ans: Relational Database Management Systems (RDBMS) are database management systems that maintain data records and indices in tables. Relationships may be created and maintained across and among the data and tables. In a relational database, relationships between data items are expressed by means of tables. Interdependencies among these tables are expressed by data values rather than by pointers. This allows for a high degree of data independence. An RDBMS has the capability to recombine the data items from different files, providing powerful tools for data usage.
Ans: PHP is a server-side scripting language commonly used for web applications. PHP has many frameworks and cms for creating websites. Even a non-technical person can create sites using its CMS.WordPress,osCommerce are the famous CMS of PHP. It is also an object-oriented programming language like java, C-sharp etc. It is very easy for learning
Ans: Relational tables have six properties:
Ans: At the lowest level, a network can consist of two or more computers directly connected by some physical medium such as coaxial cable or optical fibre. Such a physical medium is called as Link.
Ans: It is used to print data in the webpage, Example: <?PHP echo 'Car insurance'; ?>, The following code print the text in the webpage
Ans: Database normalization is a data design and organization process applied to data structures based on rules that help to build relational databases. In relational database design, the process of organizing data to minimize redundancy is called normalization. Normalization usually involves dividing a database into two or more tables and defining relationships between the tables. The objective is to isolate data so that additions, deletions, and modifications of a field can be made in just one table and then propagated through the rest of the database via the defined relationships.
Ans: A network can consist of two or more computers directly connected by some physical medium such as coaxial cable or optical fibre. Such a physical medium is called Links and the computer it connects is called Nodes.
Ans: We can include a file using "include() " or "require()" function with file path as its parameter.
Ans: De-normalization is the process of attempting to optimize the performance of a database by adding redundant data. It is sometimes necessary because current DBMSs implement the relational model poorly. A true relational DBMS would allow for a fully normalized database at the logical level while providing physical storage of data that is tuned for high performance. De-normalization is a technique to move from higher to lower normal forms of database modelling in order to speed up database access.
Ans: A node that is connected to two or more networks is commonly called a router or Gateway. It generally forwards the message from one network to another.
Ans: If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.
Ans:
Ans: If the physical links are limited to a pair of nodes it is said to be the point-point link.
Ans: require() includes and evaluates a specific file, while require_once() does that only if it has not been included before (on the same page). So, require_once() is recommended to use when you want to include a file where you have a lot of functions for example. This way you make sure you don't include the file more times and you will not get the "function re-declared" error.