SQL
What is the truncate statement used for? What is the key difference between this and your other options to remove data?
Removes all rows from a table without logging the individual row deletions. TRUNCATE TABLE is similar to the DELETE statement (with no WHERE clause); however, TRUNCATE TABLE is faster and uses fewer system and transaction log resources.
What is the generic name of the library used in .Net that is used to communicate with Databases?
What is the significance of keys in React?
Keys are used for identifying unique Virtual DOM Elements with their corresponding data driving the UI. They help React to optimize the rendering by recycling all the existing elements in the DOM. These keys must be a unique number or string, using which React just reorders the elements instead of re-rendering them. This leads to increase in application’s performance.
What is data normalization?
Database normalization, or data normalizationv, is a technique to organize the contents of the tables for transactional databases and data warehouses - to avoid redundancy
When you normalize a database, you have four goals:
i.arranging data into logical groupings such that each group describes a small part of the whole
ii.minimizing the amount of duplicate data stored in a database
iii.organizing the data such that, when you modify it, you make the change in only one place
iv.--building a database in which you can access and manipulate the data quickly and efficiently without compromising the integrity of the data in storage.
v.Normalization is usually for minimizing errors and data duplication, to DENormalize is for reporting.
What are the different parts of a Connection String?
User Id, Password, Database, Server.
What are the limitations of React?
Limitations of React are listed below:
i.React is just a library, not a full-blown framework
ii.Its library is very large and takes time to understand
iii.It can be little difficult for the novice programmers to understand
iv.Coding gets complex as it uses inline templating and JSX
What is a SQL Injection Attack and how do you protect yourself against these?
SQL injection is an attack in which malicious code is inserted into strings that are later passed to an instance of SQL Server for parsing and execution in order to effect the execution of predefined SQL commands.
A SQL Injection attack is a form of attack that comes from user input that has not been checked to see that it is valid. The objective is to fool the database system into running malicious code that will reveal sensitive information or otherwise compromise the server.
You protect from SQL Injection Attacks using a combination of stored procedures and parameters. Stored procedures alone will not protect against SQL injection attacks, because you still need use the stored procedure correctly. See here.
What are the .Net objects and classes used to communicate and execute commands at the database?
The SqlConnection Object
The SqlCommand Object
The SqlDataReader Object
The DataSet Object
The SqlDataAdapter Object
The SqlParameter Object
What are the different phases of React component’s lifecycle?
There are three different phases of React component’s lifecycle:
i.Initial Rendering Phase: This is the phase when the component is about to start its life journey and make its way to the DOM.
ii.Updating Phase: Once the component gets added to the DOM, it can potentially update and re-render only when a prop or state change occurs. That happens only in this phase.
iii.Unmounting Phase: This is the final phase of a component’s life cycle in which the component is destroyed and removed from the DOM.
If a stored procedure is too slow how can you enhance the speed?
In Sql Server Management Studio you can review the Execution Plan to ensure that "table scans" are minimized and "index scans" are used, instead. If more information is required you can use SQL Server Profiler to collect information about queries being executed and have SQL Server provide optimization recommendations.
What does it mean to be a .NET MVC application?
An application written in C# that implements the MVC design pattern, which has a high degree of separation of concern
(Follow up: The Model is properties of data, the Controller is business logic, and the View is for presentation.)
What is React Router
React Router is a powerful routing library built on top of React, which helps in adding new screens and flows to the application. This keeps the URL in sync with data that’s being displayed on the web page. It maintains a standardized structure and behavior and is used for developing single page web applications. React Router has a simple API.
explain cluster vs non cluster index
A clustered index is used to define the order or to sort the table or arrange the data by alphabetical order just like a dictionary. A non-clustered index collects the data at one place and records at another place.
Model binding retrieves data from requests, populates controller action parameters, takes care of the property mapping and type casting typically involved in working with ASP.NET request data.
What are higher order components.
Higher Order Component is an advanced way of reusing the component logic. Basically, it’s a pattern that is derived from React’s compositional nature. HOC are custom components which wraps another component within it. They can accept any dynamically provided child component but they won’t modify or copy any behavior from their input components. You can say that HOC are ‘pure’ components.