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#mysql #coding #php

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learn PHP

Hi, it’s me, Shimanta from microcodes.in. I am wishing you a very happy Christmas and also an upcoming very happy new year.

What’s new in build 221222 of our website(microcodes.in)? List of updates & changes mentioned below…

Learn PHP: There are many backend technologies in 2023 for building websites. But into them PHP is a good technology to rely on. You should choose PHP over other technologies, because there are many reasons to consider it.

Learn PHP : https://php.microcodes.in/

What you will learn in this section…

Basics of PHP – variables & operators, control statements, functions.

Data structures & OOPS – learn usages of arrays & linked-list, stack, queues. Basic OOPS concepts like encapsulation, inheritance, abstraction & exceptions.

CRUD App & Sessions: learn how to build C (Create) R (Read) U (Update) D (Delete) application using PHP & MySQL. Learn what is session, how to modify session variables usages & application.

Secure PHP – There are many way to hack a PHP application. One of the ways is SQLinjection. Learn how prepared statements helps to prevent it. Also learn pen testing tools like SQLmap, Wpscan, and Nmap etc.

We also fix many bugs of our website. We keep updated for everything including our website for making a good consumer experience.

But a small request to you if you satisfied/dissatisfied with our services, please let us know about this. For this please fill this below form which helps us to improve more for the next year.

Survey form: https://forms.office.com/r/5an1ZwH4Am

Thank you,

Shimanta Das

Website – microcodes.in

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UNION SET operator in MySQL

In MySQL, we can use various SET operators – UNION, UNION ALL, INTERSECT, MINUS.

For this article we have two sets – A(1,2,3) B(3,4,5)

UNION – The UNION operator is used to combine the result-set of two or more SELECT statements. MySQL Union is used to combine the output of two or more “SELECT” statements. The output of the “UNION” will be without duplicate rows.

We have lets UNION two above sets A and B, then it will (1,2,3,4,5)

read more: https://dbms.microcodes.in/index.php/operators/set-operators/

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maps in dart programming language

A collection of key/value pairs, from which you retrieve a value using its associated key. There is a finite number of keys in the map, and each key has exactly one value associated with it.

Maps, and their keys and values, can be iterated. The order of iteration is defined by the individual type of map. Examples:

· The plain HashMap is unordered (no order is guaranteed),

· the LinkedHashMap iterates in key insertion order,

· a sorted map like SplayTreeMap iterates the keys in sorted order.

Read more: https://dart.microcodes.in/index.php/collections/map/

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switch statement in Dart lang...

In Dart, when we handles multiple conditions that time we can use either multiple if-else statements or we can use switch statements also.

When a variable can have multiple values and for different values it will executes different statements, in that case switch statements. A switch statement is a type of selection control mechanism used to allow the value of a variable or expression to change the control flow of program execution via search and map.

Read more: https://dart.microcodes.in/index.php/control-statements/switch-statements/

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Install XAMPP server in Linux

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A.I based Gym management System:

A.I based Gym management System: https://microcodes.in/projects/1_Gym_Management_System/project.php

Features visitor's can visit website visitor's able to see pages like - trainers , stories and gallery. visiot's can contact directly Member's as well visior's also able to review. Admin can add new member for admission and also modify & delete record as well as search record in different way.

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natural join concept in SQL

A join clause in SQL – corresponding to a join operation in relational algebra – combines columns from one or more tables into a new table. ANSI-standard SQL specifies five types of JOIN: INNER, LEFT OUTER, RIGHT OUTER, FULL OUTER and CROSS. We will discuss other joins like Natural Join, EQUI Join, Self Join.

Every join maintain a principle, which is

JOIN = Cross Product + condition

Let’s start with Natural Join.

Natural Join

In natural join basically, natural join = cross product + some condition

read more: http://dbms.microcodes.in/index.php/sql-joins/join-basics/

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key concept in RDBMS

Keys – A key refers to an attribute/a set of attributes that help us identify a row (or tuple) uniquely in a table (or relation). A key is also used when we want to establish relationships between the different columns and tables of a relational database.it helps to identify a table’s record.

Super key – these are key/keys which using we can uniquely identify any table’s record uniquely.

Candidate key – candidate key is an alternative key of primary key. Using this key we can identify any table’s record uniquely. In table/relation candidate keys may be one or many attributes.

Composite key – using this key we can identify any table’s record uniquely. In table/relation these are attributes which helps to do this. We need at-least two attributes for composite keys.

Primary key – using this key we can identify any table’s record uniquely.

Foreign key – if there are two relations/tables which have the same primary key relation, then the master table’s primary key foreign key will be another child table primary key.

Important notes –

Primary key is always one/single and it can’t be a NULL state.

Super key can be one or many in the table as attributes.

Composite key will be at-least two attributes in a table/relation.

Candidate key can be one or many.

Constraints – these are some rules which apply on attributes of a relational table, to restrict user’s input data.

There is much type of constraints there –

NOT NULL constraint – if we restrict any table’s field can’t be empty, then we can use this constraint.

Unique constraint – if we restrict any table field need to maintain unique value each time, then we could use this constraint.

Default constraint – if we want any field get default value each time.

Check constraint – it checks some conditions depending upon user inputs.

Read more: http://dbms.microcodes.in/index.php/basics/keys-concepts/