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ProblemExplain the concept of reference and pointer in a c programming language using examples.ReferenceIt is the alternate name for the variable that we declared.It can be accessed by using pass by value.It cannot hold the null values.Syntaxdatatype *variablenameFor example, int *a; //a contains the address of int type variable.PointerIt stores the address of variable.We can hold the null values using pointer.It can be access by using pass by reference.No need of initialization while declaring the variable.Syntaxpointer variable= & another variable;Example Live Demo#include int main(){ int a=2, b=4; int *p; printf("add of a=%d", &a); printf("add of b=%d", &b); ... Read More
ProblemWhat are the limitations of C Programming when compared to other programming languages?SolutionC Language prevents or prohibits the concepts of object-oriented programming language like inheritance, polymorphism, encapsulation, and data abstraction.C programming language does not detect errors for every line of coding, it will check the bugs after the complete coding is done.It does not exhibit namespace property.C programming has an insufficient level for data abstraction, i.e., does not have very large data handling capacity.C Language does not allow the user to detect the errors with the help of exception handling features.The constructor and destructors concept is not supported by the ... Read More
Let us understand how to find the row that holds the maximum of a specific column in MySQL −Note: We assume we have created a database named ‘DBNAME’ and a table named ‘tableName’.Let us see how to fetch the row that holds the maximum value of a specific column using a MySQL query −This can be done using the subquery. Here, we are fetching the maximum value of colName3 −QuerySELECT colName1, colName2, colName3 FROM tableName WHERE colName3=(SELECT MAX(colName3) FROM tableName);Output+--------------+--------------+--------------+ | colName1 | colName2 | colName3 | +--------------+--------------+--------------+ ... Read More
We need to use the MAX(columnName) to find the Maximum value in a column. But, at first, we will understand about database and tables in MySQL.Before installing MySQL, it is important to determine which version and which distribution format (it could be a binary file or from source files) should be used. If the database was newly created, it is obvious that there would be no tables in it.One of the most important part is to decide the structure of the database, the tables that would be needed, the columns in every table and the relationship between these tables. Once ... Read More
Let us understand how to use MySQL wth Apache −Apache is a web server software which is developed and maintained by Apache software foundation. It is a software that takes requests from user to access a web page.A few security checks are performed on the HTTP request and then takes the user to the web page. There are many programs that allow authentication of the users from a MySQL database. These programs can also be used to write the log files into a MySQL table.The Apache logging format can be easily changed into readable mode by using MySQL, and putting ... Read More
MySQL can be run in batch mode. To perform this, the statements that need to be executed should be put in a file and then ‘mysql’ should be indicated to read the input from this file. It can be done as shown below −shell> mysql < batch−fileIf mysql is running on Windows, and there are certain special characters on the file that could potentially create problems, the below line of code can be run −C:\> mysql −e "source batch−file"If the connection parameters need to be specified on the command line, the below line of code needs to be executed −shell> ... Read More
A MySQL user name needs to be provided when ‘mysql’ is invoked. Next a password has to be entered. If the server runs on a system which is not the same as that on which the user logs in, the host name also needs to be provided while trying to log in.It is suggested to contact the administrator to find out the parameters that are required to connect to the server.Once the parameters are determined, the below lines need to be sued to connect to the server −shell> mysql −h host −u user −p Enter the password: ***Here, ‘host’ represents ... Read More
Before entering queries on the console, it is important to ensure that the user is connected to the server. The below query would give the version number of the server being used, and the current date.mysql> SELECT VERSION(), CURRENT_DATE;Note: The function ‘VERSION()’ and ‘CURRENT_DATE’ are case−insensitive. This means ‘version()’, ‘Version()’, ‘vERsion()’, all mean the same. Same goes with ‘CURRENT_DATE’An SQL query is followed by a semi-colon.When a query is issued to mysql, it sends the query to the server for execution. The results are computed and displayed. Another ‘mysql>’ also gets printed, indicating that the server is ready for one ... Read More
MySQL can be upgraded using MySQL SLES repository. Let us see the steps required for this upgradation. By default, the MySQL SLES repository updates MySQL to the latest version in the release series that the user would have chosen during installationTo update to a different release series, the subrepository for the series that has been selected needs to be disabled. It is suggested to upgrade from one series to the next, instead of skipping a series. Inplace downgrading of MySQL is not supported while using MySQL SLES repository.Upgrade MySQLUpgrade MySQL and its components using the below command −shell> sudo zypper ... Read More
The MySQL APT repository can be used to perform an in-place upgrade for the MySQL installation.It can be done using the below steps −Upgrade MySQLEnsure that MySQL APT repository is already present on user’s system's repository list.Ensure that the most up−to−date package information on the MySQL APT repository is present by running the below command −shell> sudo apt-get updateBy default, the MySQL APT repository updates MySQL to the release series that has been selected by the user when they add the MySQL APT repository to their system.In general rule, it is suggested to upgrade from one release series to another, ... Read More