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Articles on Trending Technologies
Technical articles with clear explanations and examples
What are the modes of operation in a helical antenna?
A helical antenna is another type of wire antenna, which is widely used for a higher range of broadband VHF and UHF applications. The frequency range of operation of the helical antenna is around 30MHz to 3GHz.Helical antenna or helix antenna is the antenna in which the conducting wire is wound in a helical shape and connected to the ground plate with a feeder line. It is the simplest antenna which provides circularly polarized waves and used in extra-terrestrial communications in which satellite relays etc., are involved.It consists of a helix of thick copper wire or tubing wound in the ...
Read MoreWhat is the limit of auto_increment (integer) in MySQL?
The limit of auto_increment integer depends on column data type. Displayed as follows:The data type TINYINT range is 127 The data type UNSIGNED TINYINT range is 255 The data type SMALLINT range is 32767 The data type UNSIGNED SMALLINT range is 65535 The data type MEDIUMINT range is 8388607 The data type UNSIGNED MEDIUMINT range is 16777215 The data type INT range is 2147483647 The data type UNSIGNED INT range is 4294967295 The data type BIGINT range is 9223372036854775807 The data type UNSIGNED BIGINT range is 18446744073709551615Let us take an example of TINYINT. If you will give beyond 127, then ...
Read MoreHow to encrypt the MS excel workbook?
A procedure should be followed for encrypting an MS Excel. Encryption is nothing but protecting your document from a third party. First, let us look into the definition of encryption.What is Encryption?The word encryption is derived from the Greek word Kryptos means hidden or a secret.There are certain algorithms to use encryption like RSA algorithms and Diffie-Hellman key exchange algorithms.These algorithms led to the use of encryption in commercial and consumer realms to protect data.The password is the best example of encryption.Encryption is used in sending data across all the networks and ATM is also one of the examples for ...
Read MoreHow to concat Values in MySQL Query and to handle Null values as well?
You can use CONCAT() method to concatenate values while IFNULL() method is used to handle NULL values. The syntax is as follows:SELECT CONCAT('anyStringValue:', IFNULL(yourColumnName, 'anyStringValue’)) AS anyVariableName FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table ConcatValues -> ( -> Id int NOT NULL AUTO_INCREMENT, -> FirstName varchar(20), -> MiddleName varchar(20), -> LastName varchar(20), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command. The query is as follows:mysql> insert ...
Read MoreWhat kind of jobs are there in the IT sector?
IT sector is an ever-growing industry and there is always a demand for good IT graduates in the industry. It is very important to know about the opportunities before you make a decision about your career.Jobs in Core IT sectorDevelopment of software using various computer languages and programming.Hardware support and programming, maintenance of hardware to support the developers and project managers is a more challenging and more important job for the IT professionals.Developing new sites, networking and testing are the booming career paths in IT.Providing database support, Database administration, backup of the data, these all come under database management which ...
Read MoreHow do I add more members to my ENUM - type column in MySQL?
You can use alter command. The syntax is as follows −ALTER TABLE yourTableName MODIFY COLUMN yourColumNam enum(yourOldValue1, yourOldValue2, ....N, yourNewValue1, yourNewValue2, ....N);To understand the above syntax, let us first create a table. The query to create a table is as follows −mysql> create table EnumDemo -> ( -> AllColors enum('RED', 'GREEN') -> ); Query OK, 0 rows affected (0.66 sec)Now you have two members in AllColors of enum type. If you want to add more members to your enum type, use the following query −mysql> alter table EnumDemo -> modify column ...
Read MoreExact Radius and Size of iPhone App Icons
Every iPhone application needs some icons that are displayed when certain events occur, like when some new notification comes, or the icon for home screen or the icon that is displayed on spotlight.All these icons have different size properties but apart from their size there are some common properties they have. Let’s see them first.The icons should be in .png formatThe icons should be flat and should not have transparency.The images should be squared, without any round corners.For any iOS device the icons size for app store is 1024px * 1024pxOther app icon sizes are usually bases on 1x, 2x ...
Read MoreMySQL: selecting rows where a column is null?
To select rows where a column is null, you can use IS NULL from MySQL with the help of where clause.The syntax is as follows −select *from yourTableName where yourColumnName IS NULL;Let us first create a table to understand the concept −mysql> create table NULLDemo1 -> ( -> StudentId int, -> StudentName varchar(100) -> ); Query OK, 0 rows affected (1.48 sec)Inserting records into the table. The query to insert records is as follows −mysql> insert into NULLDemo1 values(NULL, 'John'); Query OK, 1 row affected (0.25 sec) mysql> ...
Read MoreHow to select all records that are 10 minutes within current timestamp in MySQL?
You can select all records that are 10 minutes within current timestamp using the following syntax−SELECT *FROM yourTableName WHERE yourColumnName > = DATE_SUB(NOW(), INTERVAL 10 MINUTE);To understand the above syntax, let us create a table. The query to create a table is as follows−mysql> create table users -> ( -> Id int NOT NULL AUTO_INCREMENT, -> UserName varchar(20), -> UserLastseen datetime, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.91 sec)Insert some records in the table using insert command. The query is as follows−mysql> insert into users(UserName, UserLastseen) values('Larry', '2019-01-15 02−45−00'); Query ...
Read MoreSet user variable from result of query in MySQL?
To set user variable from result of query in MySQL, you need to move that variable into the assignment.To understand the above concept, let us first create a table. The query to create a table is as follows −mysql> create table UserVariable -> ( -> Id int, -> Name varchar(100) -> ); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into UserVariable values(101, 'John'); Query OK, 1 row affected (0.17 sec) mysql> insert ...
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