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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to look for partial string matches in queries in PostgreSQL?
Suppose you have a table user_info containing the names of users and their addresses. An example is given below −nameaddressAnilAndheri, Mumbai, MaharashtraJoyChandni Chowk, DelhiRonBandra, Mumbai, MaharashtraReenaOld Airport Road, Bengaluru, KarnatakaNow, if you want to just extract the information of users who stay in Mumbai, you can do that using the LIKE command and the % operator.SELECT * from user_info where address LIKE '%Mumbai%'The output will benameaddressAnilAndheri, Mumbai, MaharashtraRonBandra, Mumbai, MaharashtraNotice that we have added % operator on both sides of Mumbai. This means that anything can precede Mumbai and anything can be after Mumbai. We just want the string to ...
Read MoreHow to apply DISTINCT constraint on select columns in queries in PostgreSQL?
Suppose you have a table exam_scores containing 5 columns. An example is given below with some dummy data.nameroll_nosubjecttotal_marksmarks_obtainedAnil1English10056Anil1Math10065Anil1Science10045Roy2English10078Roy2Math10098Roy2Science10067Now, one student could have sat for exams of multiple subjects, and therefore, there are multiple rows for 1 student. If you wish to find out the total number of students in the class, you may want to find the number of distinct values of roll_no. You can apply the distinct constraint on a specific column as follows −SELECT DISTINCT ON (roll_no) name, roll_no FROM exam_scores ORDER BY roll_no DESCHere’s what the output of the above query will look like −nameroll_noRoy2Anil1You can also ...
Read MoreCASE WHEN in PostgreSQL?
If you are a programmer, you may be very familiar with IF-ELSE statements. The equivalent in PostgreSQL is CASE WHEN.Let’s understand with an example. If you have table marks containing percentage marks of a student, and you want to find out whether the students have passed or failed. An example table is given below.nameperc_marksAnil24Joy65Ron42Reena87Say the passing marks are 40. Now, if the student has scored above 40 marks, we want to print ‘PASS’ against that student’s name, otherwise ‘FAIL’. This is how you can do it −SELECT name, CASE WHEN perc_marks >= 40 THEN 'PASS' ELSE 'FAIL' END status from ...
Read MoreHow to get current timestamp and relative timestamps in PostgreSQL?
Quite often, you need the current timestamp in PostgreSQL. You do that as follows −SELECT current_timestampIt will output the current time. The output will look like the following −2021-01-30 15:52:14.738867+00Now, what if you want the relative time instead of the current time? For example, if you want the time corresponding to 5 hours prior to the current time, you can get it using intervals.SELECT current_timestamp - interval '5 hours'The output will be different every time. At the time of writing this, the output was −2021-01-30 10:57:13.28955+00 You can also do these operations on date instead of timestampsSELECT current_dateOutput2021-01-30SELECT current_date + ...
Read MoreHow to Stop the page loading in firefox programmatically in Selenium ?
We can stop the page loading in Firefox programmatically. This can be done by first setting page load time with the help of the pageLoadTimeout method.The time to wait for the page load is passed as a parameter to that method.Syntaxdriver.manage().timeouts().pageLoadTimeout(10, TimeUnit.MILLISECONDS);The page is forced to stop from loading with the help of the Javascript Executor. Selenium executes JavaScript command (window.stop() to stop page load) with the help of the executeScript method.Syntax((JavascriptExecutor)driver).executeScript("window.stop();");Exampleimport org.openqa.selenium.By; import org.openqa.selenium.WebDriver; import org.openqa.selenium.WebElement; import org.openqa.selenium.firefox.FirefoxDriver; public class StopPageLdWait{ public static void main(String[] args) { System.setProperty("webdriver.gecko.driver", "C:\Users\ghs6kor\Desktop\Java\geckodriver.exe"); ...
Read MoreCan Google Chrome be supported by Selenium IDE?
Initially Selenium IDE was used as a Firefox plugin. But the latest Selenium IDE version supports both Chrome and Firefox. For installation in Chrome, navigate to the below link −ttps://chrome.google.com/webstore/detail/seleniumide/mooikfkahbdckldjjndioackbalphokdThen click on Add to Chrome.Click on Add extension.Once installed, we shall get the below message as shown in the image −Also an icon gets created in the menu bar.Click on that icon, and the Selenium IDE gets launched with the below welcome screen.
Read MoreHow to insert values from one table into another in PostgreSQL?
Suppose you have two tables: marks and student_info. Examples are given below for the two respectivelynameroll_noperc_marksAniket1224Siddhi4565Yash2642Isha5687nameroll_noagegenderAniket1226MIsha5625FSiddhi4523FYash2625MNow, suppose your manager at work looks at the two tables and tells you, “Why do we have two tables? Simplify things, shift everything to one table!”So you decide to add the perc_marks column to the student_info table.ALTER TABLE student_info ADD COLUMN perc_marks integerNow, how will you populate this column? Will you manually add the marks for each column? That will leave the room open for a lot of errors and will also be very time-consuming. Instead, this is what you could do −UPDATE student_info ...
Read MoreHow to create nested test suites for Selenium IDE?
We can create nested test suites for Selenium IDE. A group of tests constitutes a test suite. First, to create a test suite we have to follow the below steps as listed below −Step1: Launch Selenium IDE. Then click on Create a new project link.Step2 − Provide the PROJECT NAME. Then click on OK.Step3 − Select Test Suites from the dropdown under the Project name. Then click on + button.Step4 − Add SUITE NAME, then click on ADD.Step5 − The new suite Test_Suite1 gets created. Click on it and select the option Add tests.Repeat the steps 3 and 4, to ...
Read MoreHow to give manual input from user while running Selenium IDE script?
We can give manual input from the user while running Selenium IDE script. This can be done with the help of the Command, Target and Value steps given below −Step 1Command −execute scriptTarget −return prompt("Subject","");Value −InputStep 2Command −echoTarget −${Input}Click on Run current test as highlighted in the below image.OutputA prompt for user input comes up.The text Selenium Java is entered within the prompt.Selenium IDE log captures the text entered.
Read MoreHandle Firefox Not Responding While Using Selenium WebDriver With Python?
We can handle the situation in which the Firefox is not responding with the help of the Selenium webdriver in Python. This can be achieved with the help of the FirefoxProfile class.We shall create an object of this class and apply the set_preference method on it. Then pass these preferences − dom.max_script_run_time and dom.max_chrome_script_run_time with their values set to 0 as parameters to that method.Finally, this information shall be sent to the webdriver object.Syntaxf = webdriver.FirefoxProfile() f.set_preference("dom.max_chrome_script_run_time", 0) f.set_preference("dom.max_script_run_time", 0)We can get the above parameters of the browser by following the below steps −Open the Firefox browser.Type about:config in browser ...
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