DEV Community: Ashish Pandey

What is cursor in mysql

Ashish Pandey — Sun, 27 Sep 2020 03:16:54 +0000

A database cursor is a manipulate shape that permits traversal over the archives in a database.Cursor in MySQL is nearly the identical as a cursor in different databases. MySQL cursor is a form of loop facility given to traverse in the end result of SQL one by means of one. We can function on each end result by means of the usage of the cursor in MySQL. Cursors are supported in saved procedures, functions, and triggers only. MySQL cursor is reachable from model 5 or greater. If you are looking MySQL Interview Questons then you can visit here. This will help you to crack your interviews.

MySQL cursor is read-only, non-scroll able and sensitive.

Non-scrollable

you can only fetch rows in the order decided with the aid of the SELECT statement. You can't fetch rows in the reversed order. In addition, you can't omit rows or soar to a precise row in the end result set.

Read-only

you can't replace statistics in the underlying desk thru the cursor.

A sensitive

there are two sorts of cursors: a touchy cursor and an insensitive cursor. Insensitive cursor factors to the genuine data, whereas an insensitive cursor makes use of transient replica of the data. An insensitive cursor performs quicker than an insensitive cursor due to the fact it does no longer have to make a brief reproduction of data. However, any exchange that made to the facts from different connections will have an effect on the records that is being used through an a touchy cursor, therefore, it is safer if you do now not replace the records that is being used by using an sensitive cursor. MySQL cursor is a sensitive.

Advantages of the use of Cursor

Cursors can furnish the fest few rows earlier than the total result set is assembled. Without the use of cursors, the complete end result set need to be delivered earlier than any rows are displayed with the aid of the application. So the usage of cursor, higher response time is achieved.
Using Cursor we can function row by way of row processing so we can function row smart validation or operations on every row.
Cursors can be quicker than a whilst loop however at the fee of greater overhead.
If we make updates to our except the usage of cursors in your software then we ought to ship separate SQL statements to the database server to practice the changes. This can move the opportunity of concurrency troubles if the end result set has modified on the grounds that it was once queried via the client. In turn, this raises the opportunity of misplaced updates. So the usage of cursor, higher concurrency Control can be achieved.

Disadvantages of the use of Cursor

Each time when a row is fetched from the cursor it might also end result in a community spherical trip. This makes use of lots greater community bandwidth than the execution of a single SQL declaration like SELECT or DELETE and so on that makes solely one spherical trip.
Cursor in SQL is transient work place created in the device memory, accordingly it occupies memory from your machine that may also be handy for different processes. So occupies extra sources and transient storage.
Repeated community spherical journeys can degrade the pace of the operation the usage of the cursor.

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Difference Between My SQL &PostgreSQL?

Ashish Pandey — Sun, 27 Sep 2020 03:13:51 +0000

This blog is all about the major dissimilarities between MySQL and PostgreSQL. You will be able to understand the technical differences between the two, indexes, performance, clustering, replication, and various other things. Basically, everything that you need to know about in order to understand the differences between these two.
Before moving forward, let us first understand the concept of My SQL and PostgreSQL.

What Is My SQL Actually?

MySQL is referred to as a DBMS system which is one of the most popular systems and is utilized worldwide.The name of this DBMS system is taken from the name of a girl My who. She is the daughter of Michael Widenius, the co-founder of My SQL.The source code of this system is made available under the GNU GPL. Oracle Corporation is responsible and accountable for the ownership and maintenance of this project.
MySQL is usually a Relational Database Management System (RDBMS). It mainly works on the interactive database model. With the help of it, the supervision of the database has become not only flexible but easier as well.

Now let us understand the concept of PostgreSQL

PostgreSQL is referred to as an object-relational database management system i.e. ORDBMS. It was initially developed at the University of California in the Department of Computer Science. Numerous other concepts were forged by PostgreSQL.
PostgreSQL is known as an Enterprise-class interactive database system. The installation is super easy. Also, it helps in offering support to No SQL and SQL.

MAJOR DISSIMILARITIES BETWEEN My SQL AND PostgreSQL

MySQL vs PostgreSQL

1. Source
The source code of My SQL is made accessible under the terms and conditions of the General Public License The license of PostgreSQL is an open-source license and is free of any cost. The license is made available under the PostgreSQL license. 2. Compliance with SQL The compliance of My SQL with SQL is partial. For instance, it does not provide support to check constraints.
PostgreSQL is mostly SQL compliant.
3. ACID ComplianceWhen My SQL is utilized with NDB Cluster Storage engines and InnoDB, it becomes an ACID complaint.
PostgreSQL is completely ACID compliance.
4. PerformanceThe utilization of My SQL is primarily done in the web-based projects where there is a requirement of straightforward data transactions.
The utilization of PostgreSQL is majorly done in large systems where it is imperative to read and write speeds.
5. Support by the communityMy SQL possesses a very large community of contributors. The key focus of these contributors is on sustaining existing features with the intermittently emerging new features.
The community that works for PostgreSQL actively focuses on enhancing its features. The main goal of the innovative community is to make sure that they are able to make it the most advanced database. They also concentrate on releasing security improvements and new features.
6. SuitabilityIn OLTP and OLAP systems where only read speeds are required, My SQL performs really well.
PostgreSQL performs really well when there is a requirement for executing multifarious queries.
7. Support offered to materialized viewsMySQL provides support to materialized views and temporary tables.
PostgreSQL provides support only to temporary tables and not materialized views.
8. Companies that are utilizing the productsTwitter, Uber, Airbnb
Groupon, Netflix, Instagram
9. Join competenciesLimited join competences
Good join competences
10. Forks1.6 K
2.4 K
11. GitHub Stars
3.34 K
5.6 K
12. Mass Excess Questions
532 K
89.3 K

Conclusion

Hence, if someone asks which one is better which is one of the most asked questions in My SQL interviews and PostgreSQL interview questions then, it can be clearly said that PostgreSQL edges above MySQL.

After checking out the dissimilarities between both, we have found out that My SQL has done a tremendous job of enhancing itself. On the other hand, there is no need for licensing in the case of PostgreSQL. Rules systems, database events, custom data types are also offered by PostgreSQL.

Difference Between My SQL &PostgreSQL?

Ashish Pandey — Sun, 20 Sep 2020 09:36:15 +0000

What Is My SQL Actually?

Now let us understand the concept of PostgreSQL

MAJOR DISSIMILARITIES BETWEEN My SQL AND PostgreSQL

MySQL vs PostgreSQL

	MySQL	PostgreSQL
Source	The source code of My SQL is made accessible under the terms and conditions of the General Public License	The license of PostgreSQL is an open-source license and is free of any cost. The license is made available under the PostgreSQL license.
Compliance with SQL	The compliance of My SQL with SQL is partial. For instance, it does not provide support to check constraints.	PostgreSQL is mostly SQL compliant.
ACID Compliance	When My SQL is utilized with NDB Cluster Storage engines and InnoDB, it becomes an ACID complaint.	PostgreSQL is completely ACID compliance.
Performance	The utilization of My SQL is primarily done in the web-based projects where there is a requirement of straightforward data transactions.	The utilization of PostgreSQL is majorly done in large systems where it is imperative to read and write speeds.
Support by the community	My SQL possesses a very large community of contributors. The key focus of these contributors is on sustaining existing features with the intermittently emerging new features.	The community that works for PostgreSQL actively focuses on enhancing its features. The main goal of the innovative community is to make sure that they are able to make it the most advanced database. They also concentrate on releasing security improvements and new features.
Suitability	In OLTP and OLAP systems where only read speeds are required, My SQL performs really well.	PostgreSQL performs really well when there is a requirement for executing multifarious queries.
Support offered to materialized views	MySQL provides support to materialized views and temporary tables.	PostgreSQL provides support only to temporary tables and not materialized views.

Conclusion

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How to prepare for a PHP interview?

Ashish Pandey — Sat, 09 May 2020 05:49:55 +0000

Are you going to encounter a PHP interview next week? Wondering how to prepare yourself properly, so you can get your dream job? If you have sufficient knowledge of PHP and confident about that, you are already prepared to an extent, all you need is little garnishing to enhance your confidence level and make yourself a deserving candidate.

Let’s start the preparation

Stop worrying about PHP interview questions. In this content, we are going to explore some ideas that can help an interviewee to face his or her job interview with confidence and secure their position in a respected company they desire.

Building a good resume

It is the most primary and significant factor to consider while preparing for a PHP interview. If you fail to build your resume in a proper way, it can make a bad impact on the interviewer. Following tips can help you to create a good resume.

Avoid using pictures
Including irrelevant work experience is not something of worth
Avoid making a lengthy resume
Including hobbies is not a good idea
Avoid fancy designs
Be Careful about spelling mistakes
Check grammatical errors
Avoid color resume formats, prefer black and white
The resume should be facile and readable
Do not forget to put your contact number on the first page

Preparing for interview questions

In any interview, it is very important that you know your subject properly. Before you encounter the interviewer, make sure that you have adequate knowledge about the fundamental concepts of PHP such as the followings:

What is XAMPP/ WAMP
The process of including files in PHP
Array functions
Types of errors
Forming attributes
Uploading files
File operations
Session and cookies etc

Having all the answers is certainly not possible, but feeling confident without knowing the answer is achievable. Do not hesitate to tell the interviewer if you do not have the answer of a particular question, do not let the interview to pause and think positively that you definitely have the answer for the next question.

Using the internet

In today’s context, it won’t be wrong to say that internet helps us in almost everything. You can get an idea about the PHP interview questions that are frequently asked in PHP interviews and by mastering these, you can actually increase your confidence. Thorough online research elevates your chances to crack the PHP interview and get your desired job in a reputed IT company.

Do research about the company

Before you encounter the interview, collect as much information as possible about the company that will help you to understand what they actually expect from their employees and you can prepare yourself to become one of them. You will also get to know how they conduct the interview session, what are the questions they usually ask to the interviewees.

Time is precious

Use your time as precisely and sincerely as possible to prepare for the PHP interview. Make a list of questions which require more attention and invest quality time to prepare them. Do not waste time revising the same questions in which you already feel confident.Spend time in considering about your appearance and attitude in interview as well, as first impression certainly lasts.

Note

You need to consider about certain preparations before actually encountering a PHP interview and few ideas are given above to help you in this context. Remember that confidence is the key to success and if you want to crack the interview then you have to be confident at first, and try to follow the above mentioned discussions which may assist you getting your desired job.