, Index Performance
, Employee Manager
, Cheapest Product
, Movies Live
, ATM Locations
, Delete Orders
, Restaurant Menu
, Student Activities
, Youngest Child
, Bank Branches
, Hospital Patients
, Menu Items
, Ban Users
, SMS Messages
, Student Max Score
, Department Report
, Merge Stock Index
, Weighted Average
, Language Teaching
, Read First Line
, Numbers To Text
SQL is the dominant technology for accessing application data. It is increasingly becoming a performance bottleneck when it comes to scalability. Given its dominance, SQL is a crucial skill for all engineers.
An aggregate function is typically used in database queries to group together multiple rows to form a single value of meaningful data. A good programmer should be skilled at using data aggregation functions when interacting with databases.
Subqueries are commonly used in database interactions, making it important for a programmer to be skilled at writing them.
The proper implementation and use of indexes are important for improving the performance of database queries.
Conditional statements are a feature of most programming and query languages. They allow the programmer to control what computations are carried out based on a Boolean condition.
Even though most database insert queries are simple, a good programmer should know how to handle more complicated situations like batch inserts.
A programmer should use a language as a tool, always taking advantage of language-specific data types and built-in functions.
A normalized database is normally made up of multiple tables. Joins are, therefore, required to query across multiple tables.
Constraints are used to define rules and relationships. They are applied to a dataset. A constraint may take many forms, such as x ≤ 5 in a programming language and a NOT NULL constraint in a SQL table definition.
A database schema defines how data is stored in a database. An SQL database uses a schema to define tables consisting of rows and columns that use fixed data types to store data. Formalizing how data is stored is the first step towards building an application or service.
Everyone makes mistakes. A good programmer should be able to find and fix a bug in their or someone else's code.
The delete statement is used to delete records in a table and is one of the four basic CRUD functions (create, read, update, and delete) required for working with any persistent storage.
The UPDATE statement is used to modify the existing records in a table and is one of the most used operations for working with the database.
A database view is a result set that is defined by a stored query, the results of which can can also be queried. As a fundamental and widely used database construct, it's useful for candidates to understand how and when they should be used.
The performance of an application or system is important. The responsiveness and scalability of an application are all related to how performant an application is. Each algorithm and query can have a large positive or negative effect on the whole system.
The UNION operator is used to combine the result-set of two or more SELECT statements. It is often used when a report needs to be made based on multiple tables.
Scala a general-purpose, functional programming language with a strong static type system. Designed to be concise, many of Scala's design decisions were inspired by criticisms of Java's shortcomings. Having a basic familiarity with the programming language used on the job is a prerequisite for quickly getting up to speed.
A collection is a grouping of a variable number of data items. Many programming languages implement support for custom collections in their class libraries or utilities, as such it's an important topic for a developer to be familiar with.
As opposed to strict evaluation, which runs code immediately when encountered, in lazy evaluation code evaluation is deferred until the value is needed. This provides the benefits of potential performance increases.
Exceptions exist in most modern programming languages, making it important for a programmer to understand them and know how to handle them.
Object-oriented programming is a paradigm based on encapsulating logic and data into objects, which may then contain fields and procedures. Many of the most widely used programming languages are based on OOP, making it a very important concept in modern programming.
The string data structure is used to represent text. It is one of the most commonly used data structures. Therefore, every programmer should be skilled at string manipulation.