Online Visitor Tracking System using CodeIgniter 4, MySQL 8 and AJAX

In this tutorial I am going to show you how you can build an online visitor tracking system using PHP based framework CodeIgniter 4, MySQL 8 and AJAX technique. The similar system for tracking online visitors on web site, I built in past, using CodeIgniter 3 framework. As a web site owner you would like to the progress to the count of your visitors, page views, etc. because, it gives you overall idea on the website’s analytical measurements. It will also give you how you can make improvements to your…

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SELECT list is not in GROUP BY clause and contains nonaggregated column – mysqli_sql_exception #1055

You might encounter the following issue while executing an SQL query qith Group By clause in MySQL database server. Error Type: mysqli_sql_exception #1055 Error Details: Expression #2 of SELECT list is not in GROUP BY clause and contains nonaggregated column ‘roytuts.visitors.access_date’ which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

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How to deploy Spring Boot Data JPA Application to Heroku Cloud

In this tutorial I am going to show you an example on deploying Spring Boot application to Heroku cloud. I will create a basic CRUD application with Spring Boot Data JPA and PostgreSQL/MySQL technologies. I will first show you how to perform CRUD operations locally, then deploy the same application in the Heroku cloud with some modifications. CRUD is an acronym that stands for Create, Read, Update and Delete. I am building REST APIs using Spring Boot framework. I will use Postman tool to access and test the REST web…

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How to install PostgreSQL Zip Archive in Windows

In this example I will show you installing PostgreSQL zip archive in Windows environment. I will show you how to setup username and password for your PostgreSQL database server. I am also going to show you some basic commands for listing all database, switching to another database, creating a new database, showing all tables, creating a new table, database backup, database import. The advantage of installing zip version of the PostgreSQL is that your registry does not get modified and you do not need to restart your system (if required).…

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How to delete Duplicate Records from MySQL Table

This example will show you how to delete or eliminate duplicate records from a table in database. Keeping duplicate records in a table is unnecessary and it also grows the size of database unnecessary. Removing duplicate records from the table will free the occupied space and enhance also the performance of the query execution. Let’s say you have the following data in your database table. The table name is teacher. The following table has some duplicate records. Now I will show you how to remove duplicates from the below table.

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Sort MySQL Table Data in Ascending or Descending Order in CodeIgniter 4

In this tutorial I am going to show you how to sort MySQL table data in ascending or descending order to display them on HTML table on user interface (UI) using Codeigniter 4. I had also shown similar example using CodeIgniter 3. So when a user wants to see the data on UI either in ascending or descending order then the user needs to click on the table column header to sort the data on HTML table. I have created href link on the HTML table’s column header to make…

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MongoDB Aggregation Operations

You are not going to always return records from MongoDB but sometimes you need to perform some computations such as sum, count, average, etc. Here you need the aggregation operations which are used to process data that return the computed results. Therefore aggregation actually groups data from multiple documents and performs a variety of operations on the grouped data to return the single result. Aggregate operations retrieve a single value after performing a calculation on a set of values. Often aggregate functions are accompanied by group clause in the find()…

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MongoDB find() method with Projection

You may not want to fetch a whole bunch of data from the document which is stored in a collection in your MongoDB database. You can restrict the number of records or data using different conditions with the help of WHERE, AND, OR and IN operators, but what if you want to restrict the data you want in your particular row or record or document. So here comes the projection that helps you to selectively choose data from a record or row or document. In MongoDB, projection means selecting only…

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How to query documents – WHERE, AND, OR, IN conditions in MongoDB

MongoDB is one of the most popular NoSQL database where data are stored in the form of documents. You can also create tables in traditional way to put your structured data but the main purpose is to store unstructured data in the form of object which may vary based on a particular requirement. Now when you select data from collection, you may not need all data to be fetched from the database collection and you want to restrict those data based on certain criteria or conditions while fetching from database.…

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How to make output of MongoDB’s find() readable in shell

MongoDB is one of the most popular NoSQL database where your data are stored in a collection. To quickly access your data from MongoDB you can execute commands on MongoDB shell and your results appear based on the given criteria. One of the commands is find() function and using this command you can easily retrieve data from MongoDB collection. When you execute this find() command to retrieve data from a collection, it displays data in one line which makes it ugly and become difficult to read specially when there multiple…

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