While creating a table (email_notifications), we were facing this error type “citext” does not exist. The syntax of creating table and the error is shown in the screenshot below :
Then Read more…
Resolved Issue
“Invalid value for header \u0067x-ms-request-id\u0067. The header must contain a single valid GUID”
I was facing the issue “Invalid value for header \u0067x-ms-request-id\u0067. The header must contain a single valid GUID” while making request to the Read more…
“Invalid value for header \u0067x-ms-request-id\u0067. The header must contain a single valid GUID”
I was facing the issue “Invalid value for header \u0067x-ms-request-id\u0067. The header must contain Read more…
First download the aws library using the this link:
http://docs.aws.amazon.com/aws-sdk-php/v3/download/aws.zip link and save it in project.
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Now the usage of library Read more…
While trying to connect to Postgress you may face this error – Server doesn’t listen.
Error:
This is not an error exactly but an exception that occurs when we are running two Read more…
1. Avoid usage of multiple joins in a single query. Unnecessary joins degrade your query performance.
2. Creation of indexes on the table. Indexes are used for improving your queries. We need to create the indexes Read more…
There is a lot of discussion on internet about whether to have DAOs or not with JPA and service layer or with session beans (which is the service layer).
My personal opinion is more favored towards DAO layer and some reasons for this are following:
1. In most of the Read more…
MySql Communication link failure while connecting MySql server remotely
I’m getting the following error when I tried to connect MySql server remotely:
ERROR:
——————————————
Cannot connect to database server
Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not Read more…
Sometimes, we want to show only those columns which have specific value. Let’s assume we have following table :
In the above table, value of 1 in a column represents that corresponding service is provided by organization and 0 represents service is not provided by the organization.
In the above Read more…
SQL transaction in Cakephp 3 is a series of statements working in a logical order to handle database errors and ensure data integrity. There are four main methods being used in Sql transaction in Cakephp 3.
1. Initialize the statement using begin() method.
2. Execute the statement which Read more…
Azure provides various rest apis to perform different actions and operations that are possible in the azure server like to create web applications, databases and many more. User can design their own simplified UI to perform actions, instead of logging into Azure and perform all the steps one by one Read more…
Suppose we have two tables : articles and article_comments
CREATE TABLE articles(
`id` INT( 11 ) NOT NULL AUTO_INCREMENT ,
`title` VARCHAR( 200 ) NOT NULL ,
`content` VARCHAR( 500 ) NOT NULL ,
`author_name` VARCHAR( 20 ) DEFAULT 1 NOT NULL ,
`author_email` VARCHAR( 50 ) NOT NULL ,
`created_date` TIMESTAMP NOT NULL DEFAULT ‘0000-00-00 00:00:00 Read more…
Sometimes requirement arises to display a field value as column name in output and adjacent values in the same row below it as its values.
Suppose I have a table “students” with marks of each student in different subjects. Each student may not appear in every subject:
students
We want Read more…
Create and Download CSV of table Records using OUTFILE Sql command and PHP
1. Create temporary CSV file using OUTFILE SQL command: OUTFILE command is used to write your sql command output to the specified location. You can write the output to some files using OUTFILE when required Read more…
SQL Report in ‘Configurable Reports’ plugin provides us an easy UI to write SQL Query and draw results immediately without involving any code complications.
Suppose I want to generate my custom grades report based on some specific activities from course – Let’s say these are PreTest 1, Pretest 2 and Read more…
‘Like’ operator of SQL can be used in the following ways in Moodle:
Using expression $DB->sql_like:
$grade_item_test = $DB->get_records_sql ( ‘SELECT * FROM {grade_items} WHERE
‘.$DB->sql_like(‘idnumber’, ‘:idnum’).’ AND courseid=:cid order by itemmodule’,
array (‘idnum’=>’test’,’cid’=> $courseid) );
Using like operator:
$grade_item_test = $DB-> Read more…
JSONB (JSON Blob) datatype in Postgres is used to save JSON data. We can search on JSONB type of column after creating an index on it.
For example:
Usage in PostgreSQL:
1. Create table and index
CREATE TABLE tests
(
id integer NOT NULL,
email citext NOT NULL,
address jsonb NOT Read more…
MySQL access Denied for user while Username and password is correct.
I got this error when I named one of my table columns as “order” which is also a mysql keyword. When tried to rename it, I got the following error on execution.
ERROR 1045 (28000): Access denied Read more…
Purpose is to automate most of recurring processes like creating user, installing application (apache, apache-tomcat, mysql-server …etc), and modifying security file to hardening Linux machines in AWS environment.
1. Click AWS OpsWorks option from AWS console panel:
2. Now click on Add Stack to create a new Stack Read more…
AWS WAF web application firewall service is built to protect cloud apps from web attacks like DDoS attacks, SQL injections, Cross site scripting.
Below are the steps involved in configure AWS WAF security:
Step.1 Open CloudFormation and click on create new Stack.
Step.2 Select the option (Specify an Read more…
