Q1151. NOT NULL constraint?
The **`NOT NULL`** constraint enforces that a column must always contain a valid data value and cannot accept `NULL`: ```sql CREATE TABLE employees ( id INT PRIMARY KEY, ...
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Q1152. How to convert a string to lowercase in Python?
Use the `.lower()` or `.casefold()` string method in Python: ```python s = 'MYSTRING' print(s.lower()) # Output: 'mystring' ``` *Tip:* `.casefold()` is recommended for ca...
Q1153. What is the difference between flex-grow and flex-shrink properties in Flexbox?
`flex-grow` is a property in Flexbox that specifies how much a flex item should grow relative to the other items in the container, while `flex-shrink` specifies how much ...
Q1154. What are global variables?
Global variables are those that are available throughout the length of the code without any scope. The var keyword is used to declare a local variable but if you omit it ...
Q1155. Why you get "Router may have only one child element" warning?
You have to wrap your Route's in a `` block because `` is unique in that it renders a route exclusively. At first you need to add `Switch` to your imports: ```javascript ...
Q1156. What is the difference between pages and components directories?
In professional Next.js architecture, separating **`pages`** (or `app`) from **`components`** is fundamental to project organization: | Aspect | `pages/` (or `app/`) | `c...
Q1157. What are functional components?
The functional components are just simple functions to create simple components just by passing a context. Every functional component follows two rules, 1. **Stateless:**...
Q1158. An unique (non-key) field?
To enforce that every value in a non-primary key column is unique, apply the **`UNIQUE`** constraint: ```sql CREATE TABLE users ( id INT PRIMARY KEY, email VARCHAR(255) U...
Q1159. How to check if string A is substring of string B?
The most readable, pythonic, and performant way to check if substring A exists inside string B is using the **`in` operator**: ```python str_b = "HireXTech Interview Prep...
Q1160. What is the difference between flex-wrap: nowrap and overflow: hidden in CSS?
`flex-wrap: nowrap` prevents flex items from wrapping to the next line when they overflow the container, while `overflow: hidden` hides any content that overflows the con...