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Articles by radhakrishna
Page 6 of 7
What is the use of MySQL LAST_INSERT_ID() function?
MySQL LAST_INSERT_ID() function is used to obtain the most recent generated sequence number by AUTO_INCREMENT.ExampleIn this example, we are creating a table named ‘Student’ having an AUTO_INCREMENT column. We insert two values in the column ‘Name’ and when we use INSERT_LAST_ID() function then it returns the most recent generated sequence number i.e. 2.mysql> Create table Student(Id INT PRIMARY KEY NOT NULL AUTO_INCREMENT, Name Varchar(5)); Query OK, 0 rows affected (0.13 sec) mysql> Insert into student(Name) Values('Raman'); Query OK, 1 row affected (0.06 sec) mysql> Insert into student(Name) Values('Rahul'); Query OK, 1 row affected (0.07 sec) mysql> Select* ...
Read MoreWhat is the difference between CHAR and VARCHAR in MySQL?
CHAR and VARCHAR are both ASCII character data types and almost same but they are different at the stage of storing and retrieving the data from the database. Following are some important differences between CHAR and VARCHAR in MySQL −CHAR Data TypeVARCHAR Data TypeIts full name is CHARACTERIts full name is VARIABLE CHARACTERIt stores values in fixed lengths and are padded with space characters to match the specified lengthVARCHAR stores values in variable length along with 1-byte or 2-byte length prefix and are not padded with any charactersIt can hold a maximum of 255 characters.It can hold a maximum of ...
Read MoreHow can I convert Python dictionary to JavaScript hash table?
Python and javascript both have different representations for a dictionary. So you need an intermediate representation in order to pass data between them. The most commonly used intermediate representation is JSON, which is a simple lightweight data-interchange format.The dumps function converts the dict to a string. exampleimport json my_dict = { 'foo': 42, 'bar': { 'baz': "Hello", 'poo': 124.2 } } my_json = json.dumps(my_dict) print(my_json)OutputThis will give the output −'{"foo": 42, "bar": {"baz": "Hello", "poo": 124.2}}'exampleThe load's function converts the string back to a dict. import json my_str = '{"foo": 42, "bar": {"baz": "Hello", "poo": 124.2}}' my_dict ...
Read MoreHow can we import data from .txt file into MySQL table?
It can be done with the help of LOAD DATA INFILE statement. To illustrate the concept we are having the following data, separated by tab, in ‘A.txt’ whose path is d:/A.txt −100 John USA 10000 101 Paul UK 12000 102 Henry NZ 11000 103 Rick USA 17000 104 Corey USA 15000We want to load the data of A.txt into the following table named employee_tbl −mysql> Create table employee_tbl(Id Int, Name varchar(20), Country Varchar(20), Salary Int); Query OK, 0 rows affected (0.91 sec)Now, the transfer of data from a file to a database table can be done with the help ...
Read MoreHow can we ignore the negative values return by MySQL DATEDIFF() function?
As we know that DATEDIFF() function is used to get the difference in a number of days between two dates. Hence, it is quite possible that it returns negative value as well.mysql> select * from differ; +------------+-------------+ | OrderDate | WorkingDate | +------------+-------------+ | 2017-10-22 | 2017-10-29 | | 2017-10-25 | 2017-10-30 | | 2017-10-25 | 2017-11-30 | +------------+-------------+ 3 rows in set (0.00 sec)Above query will return the values from table ‘differ’. Now, if someone wants to get the difference between OrderDate and WorkingDate then the output would be negative as follows −mysql> Select DATEDIFF(OrderDate, WorkingDate)AS 'DIFFERENCE IN DAYS' ...
Read MoreHow can we know about the starting range of TIMESTAMP data type with the help of MySQL FROM_UNIXTIME() function?
As we know that this function converts a number of seconds into TIMESTAMP value. So by providing 0 seconds as the argument, it will give us the starting range of TIMESTAMP data type.mysql> Select FROM_UNIXTIME(0); +-------------------------+ | FROM_UNIXTIME(0) | +-------------------------+ | 1970-01-01 05:30:00 | +-------------------------+ 1 row in set (0.00 sec)Now if we will change the argument from 0 to 60 seconds then the time will be changed by 01 minutes.mysql> Select FROM_UNIXTIME(60); +-------------------------+ | FROM_UNIXTIME(60) | +-------------------------+ | 1970-01-01 05:31:00 | +-------------------------+ 1 row in set (0.00 sec)
Read MoreWhat is the difference between non-static methods and abstract methods in Java?
Following are the notable differences between non-static methods and abstract methods.Non-static (normal) methodsAbstract methodsThese methods contain a body.Abstract methods don’t have body these are ended with a semicolonYou can use normal method directly.You cannot use abstract methods directly, to use them you need to inherit them and provide body to these methods and use them.Example:public void display() { System.out.println("Hi"); }Example:public void display();
Read MoreWhat is the difference between Java and Core Java?
Java is a programming language, whereas Core Java is a computing platform. Java Platform Standard Edition is Core Java, which is also called Java SE. The following are the computing following supported by Java, which also has Core Java as its part:Java SE Java Standard Edition used to develop desktop applications. A well-known implementation of Java SE is the Java Development Kit (JDK).Java EE Java Enterprise Edition i.e. Java 2 Platform, Enterprise Edition or J2EE. Java EE is used for applications running on servers. Java ME Java Micro Edition is used for applications running on mobile phones.Java SE is the Standard Edition and also ...
Read MoreWhy can't static method be abstract in Java?
A static method belongs to class not to object instance thus it cannot be overridden or implemented in a child class. So there is no use of making a static method as abstract.
Read MoreHow to avoid Java code in jsp page?
You can use JSTL, JSP Standard Tag Library or EL, Expression Language to avoid scriptlets.
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