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MySQL implements a sophisticated access control and privilege system that allows us to create comprehensive access rules for handling client operations and effectively preventing unauthorized clients from accessing the database system.The MySQL access control has two stages when a client connects to the server −Connection verification A client, which connects to the MySQL database server, needs to have a valid username and password. In addition, the host from that the client connects needs to match with the host within the MySQL grant table.Request verificationonce a connection is established successfully, for each statement issued by the client, MySQL checks whether the client ... Read More
A class constructor is a special member function of a class that is executed whenever we create new objects of that class.A constructor has exactly the same name as that of class and it does not have any return type.Constructor has the same name as the class name −class Demo { public Demo() {} }The following is an example −Example Live Demousing System; namespace LineApplication { class Line { private double length; // Length of a line public Line() { Console.WriteLine("Object is being created"); ... Read More
When we install MySQL server, a database named MySQL created automatically. This MySQL database contains five main grant tables with the help of which MySQL server can control the privileges of MySQL database server. These tables are as follows −user tableThis table contains user account and global privileges columns. MySQL uses the user table to either accept or reject a connection from a host. A privilege granted in the user table is effective to all databases on the MySQL server.db tableThis table contains database-level privileges. MySQL uses the db table to determine which database a user can access and from which host. ... Read More
In C#, some identifiers have special meaning in context of code, such as get and set are called contextual keywords.The following is the table showing contextual keywords −Contextual Keywordsaddaliasascendingdescendingdynamicfromgetglobalgroupintojoinletorderbypartial (type)partial(method)removeselectset
It is quite possible to allow a user account to connect from any host. To do so we need to create the user with the help of ‘%’ wild card character after @ character. Its syntax would be as follows −Use mysql; CREATE USER user_name@’%’ IDENTIFIED BY password;Here user_name is the name of the user we wish to make an account for.Password is the password we wish to make for user_account. With the help of this password, MySQL server will identify this user.ExampleIn the given example we are creating a user ‘Gaurav’ by using ‘%’ character so that it can be ... Read More
Dynamic arrays are growable arrays and have an advantage over static arrays. This is because the size of an array is fixed.To create arrays dynamically in C#, use the ArrayList collection. It represents an ordered collection of an object that can be indexed individually. It also allows dynamic memory allocation, adding, searching and sorting items in the list.The following is an example showing how to create arrays dynamically in C# −Example Live Demousing System; using System.Collections; namespace Demo { class Program { static void Main(string[] args) { ArrayList al = new ArrayList(); ... Read More
To make it understand, we are using the following data from a table named ‘customerdetail’.mysql> Select * from Customerdetail; +----------------------+----------------------+----------+---------------------+ | Name | FName | Address | Emailid | +----------------------+----------------------+----------+---------------------+ | Advik Jhamb | Lovkesh Jhamb | Mumbai | Advik@gmail.com | | Chirag Jai Patil | Raman Jai Patil | Gujrat | chirahp@yahoo.com | | Devansh Singh Rajput | Kishore Singh Rajput | ... Read More
MySQL TRIM() function is used to remove all the suffixes or prefixes or both from the string. The working of TRIM() function can be understood with the help of its syntax −SyntaxTRIM([{BOTH | LEADING | TRAILING} [str_to_remove] FROM] string)Here, the argument BOTH means the prefixes from both left and right to be removed from the string.LEADING argument means that only leading prefixes to be removed.TRAILING argument means that only trailing prefixes to be removed.Str_to_remove is the argument which means the string we want to remove from the string.String argument means the string from which the prefixes have to be removed.Examplemysql> ... Read More
The null coalescing operator is used with the nullable value types and reference types. It is used for converting an operand to the type of another nullable (or not) value type operand, where an implicit conversion is possible.If the value of the first operand is null, then the operator returns the value of the second operand, otherwise, it returns the value of the first operand.The following is an example −Example Live Demousing System; namespace Demo { class Program { static void Main(string[] args) { double? num1 = null; ... Read More
If we omit the hostname part of the user account, MySQL will accept it and allow the user to connect from any host. Its syntax would be as follows −Use mysql; CREATE USER user_name IDENTIFIED BY password;Here, user_name is the name of the user we wish to take account of.Password is the password we wish to make for user_account. With the help of this password, MySQL server will identify this user.ExampleIn the given example we are creating a user ‘REMOTE’ by omitting the host name.mysql> CREATE USER remote identified by 'password123'; Query OK, 0 rows affected (0.00 sec)The user ‘Remote’ can ... Read More