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Articles on Trending Technologies
Technical articles with clear explanations and examples
What are the differences between JFrame and JDialog in Java?\\n
JFrameThe components added to the frame are referred to as its contents, these are managed by the contentPane. To add a component to a JFrame, we must use its contentPane instead.A JFrame contains a window with title, border, (optional) menu bar and user-specified components.A JFrame can be moved, resized, iconified and it is not a subclass of JComponent.By default, JFrame is displayed in the upper-left corner of the screen. To display a frame at a specified location, we can use the setLocation(x, y) method in the JFrame class.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class JFrameDemo { public static void main(String s[]) { ...
Read MoreWhat are the different wildcard characters which can be used with NOT LIKE operator?
As we know that NOT LIKE operator is used along with WILDCARD characters for not getting the string having specified string. Basically, WILDCARD is the characters that help search data matching complex criteria. Followings are the types of wildcard which can be used in conjunction with NOT LIKE operator:% - The PercentageThe ‘%’ wildcard is used to specify a pattern of 0, 1 or more characters. A basic syntax for using % wildcard with NOT LIKE operator is as follows:Select Statement…Where column_name NOT LIKE ‘X%’Here X is any specified starting pattern such as the single character of more and % matches ...
Read MoreIn MySQL, how can we check whether a string of a specified pattern is not present within another string?
We can check whether a string of specified pattern is not present within another string by using NOT LIKE operator along with wildcard characters.SyntaxNOT LIKE specific_patternSpecific_pattern is the pattern of string we do not want to find out within another string.ExampleSuppose we have a table named ‘student’ having names of the students and we want to get the details of all those students which are not having a pattern of string ‘av’ within their names. It can be done with the help of following MySQL query:mysql> Select * from Student WHERE name NOT LIKE '%av%'; +------+---------+---------+----------+--------------------+ | Id ...
Read MoreHow can we take a backup of a particular table from a database by using mysqldump client program?
By using mysql dump client program we can take the backup of a particular table from the databases into a file having the extension ‘.sql’. It can be understood with the help of the following example −ExampleIn this example, with the help of mysql dump client program, we are taking the backup of a table named ‘student_info’ from ‘query’ database in a file named ‘student_info.sql’. The following command will do this:C:\mysql\bin>mysqldump -u root query student_info > student_info.sqlThe above command will create a file named student_info.sql which has the dump information of a file named ‘student_info’ from database named ‘query’.
Read MoreWhat are the similarities and differences between MySQL ORD() and ASCII() functions?
MySQL ORD() function returns the code for the leftmost character if that character is a multi-byte i.e. sequence of one or more bytes, with the help of the following formula(1st bytecode) + (2nd bytecode * 256) + (3rd bytecode * 256^2)On the other hand, ASCII() function returns the ASCII value of the leftmost character of a given string.The difference between them lies on the point that whether the leftmost character is a multi-byte character or not. If it is not a multi-byte character then both ORD() and ASCII() functions return similar results. Following example will demonstrate it.mysql> Select ORD('Tutorialspoint'); +-----------------------+ ...
Read MoreHow can I use MySQL OCTET_LENGTH() function to count the number of characters stored in a data column?
We need to pass the column name as the argument of OCTET_LENGTH() function to count the number of characters stored in a data column. It displays the number of characters when referenced in SELECT clause. It can also be used as comparison value to decide whether or not the row should returned by using it in WHERE clause. The contents of ‘Student’ table are used to demonstrate it −mysql> Select Name, OCTET_LENGTH(Name)As 'Str_Length' from Student; +---------+------------+ | Name | Str_Length | +---------+------------+ | Gaurav | 6 | | Aarav | 5 ...
Read MoreHow can we take a backup of all the databases by using mysqldump client program?
By using mysql dump client program we can take the backup of all the databases into a file having the extension ‘.sql’. It can be understood with the help of the following example −ExampleIn this example, with the help of mysql dump client program, we are taking the backup all the databases in a file named ‘alldatabases.sql’. The following command will do this −C:\mysql\bin>mysqldump -u root --all-databases > alldatabases.sqlThe above command will create a file named alldatabases.sql which has the dump information of all the databases.
Read MoreHow can I restore a database dumped by mysqldump?
Suppose if we have dumped the whole database and now want to restore it then we can do it with the following example −C:\mysql\bin>mysql -u root query < tutorials.sqlWith the help of above query, we are restoring the dumped database named ‘tutorials’, in the file tutorials.sql, into other database named ‘query’. It means that the tables of database ‘tutorials’ would be restored in a database named ‘query’.
Read MoreWhat MySQL TRIM() function returns if 1st argument(i.e. BOTH, LEADING, TRAILING) is not specified?
By default MySQL will assume the argument BOTH if the 1st argument is not specified in TRIM() function. Following example will demonstrate it.Examplemysql> SELECT TRIM('A' FROM 'ABCDAEFGAA'); +-----------------------------+ | TRIM('A' FROM 'ABCDAEFGAA') | +-----------------------------+ | BCDAEFG | +-----------------------------+ 1 row in set (0.00 sec)The above result set shows that when we did not specify 1st argument then MySQL returns the output by assuming BOTH as the 1st argument of TRIM() function.
Read MoreWhat would be the output of MySQL SUM() function if a column having no values has been passed as its argument?
When MySQL SUM() function got a column, having no values, as an argument then it will return NULL, rather than 0, as output. The column can be of any data type. Following the example, using a table named ‘social’ having only one column named ‘id’ with no values, will illustrate itExamplemysql> Describe Social; +-------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+-------------+------+-----+---------+-------+ | Id | int(11) | YES | | NULL | | | Name | varchar(20) | YES | ...
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