Regular Expressions Quiz: Master Regex with Flashcards

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Questions and Answers

What function is used to query or read from a collection in MongoDB?

find()

When the find() function is used without any filter or criteria, what does it retrieve?

all the documents in the collection

When the find() function is used with a filter or criteria, what does it retrieve?

only the documents which match the criteria

What are some limitations of MongoDB?

<ol> <li>MongoDB doesn't support joins like a relational database. 2. High memory usage due to key names for each value pair and data redundancy. 3. Limited data size of 16MB per document. 4. Limited nesting of documents for more than 100 levels.</li> </ol> Signup and view all the answers

What is a NoSQL database?

A NoSQL database is a database that provides a mechanism for storage and retrieval of data, using data structures different from those used in relational databases. Signup and view all the answers

What are some advantages of NoSQL databases compared to relational databases?

Some advantages of NoSQL databases include simplicity of design, simpler horizontal scaling to clusters of machines, finer control over availability, and data structures that are sometimes viewed as more flexible. Signup and view all the answers

What are some characteristics of NoSQL databases?

Some characteristics of NoSQL databases include the ability to handle data clustering, the prevalence of open-source solutions, being built for the web, lack of a fixed schema, and a growing connection between the data requiring an architecture. Signup and view all the answers

Why are relational databases not well-suited for storing large amounts of data?

The relational model is fairly rigid, making changing an existing structure time-consuming. Additionally, relational databases can have very large tables with bloated records. Signup and view all the answers

What is the difference between SQL and NoSQL databases?

SQL databases are relational and have a fixed schema, while NoSQL databases are non-relational and have a dynamic schema. Signup and view all the answers

What are the limitations of NoSQL databases?

NoSQL databases often compromise consistency for availability and partition tolerance, and they are not as good for complex queries. Signup and view all the answers

What is MongoDB and what are its advantages?

MongoDB is an open source NoSQL database that stores data in JSON-like documents. It offers high performance, high availability, automatic scaling, and a flexible data model. Signup and view all the answers

What is the purpose of regular expressions in text search?

Regular expressions are used to retrieve specific patterns or words in text search. Signup and view all the answers

How can regular expressions be used to retrieve names with specific words?

Regular expressions can be used to retrieve names with specific words by using the $regex operator in the query with the desired pattern. Signup and view all the answers

What does the query 'db.products.find( { sku: { $regex: /789$/ } [ }' find?

The query finds documents in the 'products' collection where the 'sku' field ends with '789'. Signup and view all the answers

How can a new database be created or switched to in MongoDB?

To create a new database or switch to a previously created database, the 'use' command is used, followed by the name of the database, e.g. 'use weatherdb'. Signup and view all the answers

Study Notes

NoSQL Databases

NoSQL databases provide a mechanism for storage and retrieval of data, modeled in means other than the tabular relations used in relational databases.
They are used in real-time web applications and big data, and their use is increasing over time.
NoSQL systems are also sometimes called "Not Only SQL" to emphasize the fact that they may support SQL-like query languages.

Characteristics of NoSQL Databases

Simplicity of design
Simpler horizontal scaling to clusters of machines
Finer control over availability
Data structures used are different from those used by default in relational databases, making some operations faster
The suitability of a given NoSQL database depends on the problem it should solve
Data structures used are sometimes also viewed as more flexible than relational database tables

What is Not NoSQL

NoSQL does not mean the absence of SQL; instead, it means "Not Only SQL"
There is no fixed definition for what NoSQL is or does, but the following concepts can help us understand what NoSQL is (and isn't):
- No relational model
- Data can be clustered
- Most solutions are open-source
- Built for the Web
- Lack of a schema

Why NoSQL

Relational databases are not suitable for large amounts of data and changing structures
Structured data is arranged in neat rows and columns, but unstructured data isn't organized and doesn't follow strict patterns
NoSQL databases are not tied to a rigid structure and offer things like a clustered approach that can improve performance

SQL vs NoSQL

SQL: Relational Database Management System (RDBMS)
- Fixed or static schema
- Not suited for hierarchical data storage
- Best suited for complex queries
- Vertically Scalable
NoSQL: Non-relational or distributed database system
- Dynamic schema
- Best suited for hierarchical data storage
- Not so good for complex queries
- Horizontally scalable

Aggregate Data Models

Used in NoSQL databases
Flexible data model
More scalable and performant than relational data models

Limitations of NoSQL

Joins not supported
High memory usage
Limited data size (16MB)
Limited nesting (100 levels)

MongoDB

Open-source NoSQL database
Stores data in JSON-like documents
Provides high performance, high availability, and automatic scaling
Uses a distributed database system
Compromises consistency in favor of availability and partition tolerance
Uses "eventual consistency" to achieve speed and scalability

MongoDB Query Language

Uses BSON (Binary JSON)
Similar to SQL
Used to query and retrieve data from MongoDB

MongoDB Data Structure Organization

Database is a physical container for collections
Each database gets its own set of files on the file system
A single MongoDB server typically has multiple databases
Uses name-value pairs or fields, which then make up documents, which make up collections

MongoDB Querying

Uses the find() method to query and retrieve data
Can use regular expressions to search for patterns in strings
Supports arrays and nested documents

Regular Expressions in MongoDB

Used to search for patterns in strings
Supports PCRE (Perl Compatible Regular Expression) syntax
Used to retrieve data that matches a specific pattern

MongoDB Client-Server Architecture

Uses a client-server architecture
Server (mongod) should be started before connecting using the client (mongo)
Client can be used to connect to the server and perform queries

Creating and Using a Database in MongoDB

Uses the use command to create a new database or switch to a previously created database
Uses the show collections command to list the collections in the database
Uses the insert() function to insert data into a collection
Uses the insertMany() function to insert multiple documents into a collection

Updating and Deleting Data in MongoDB

Uses the update() function to update data in a collection
Uses the remove() function to delete data from a collection
Supports updating and deleting data using criteria and filters

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Description

Test your knowledge of regular expressions with this quiz! Learn how to use regular expressions for text search and perform advanced searches with ease. Challenge yourself with examples and practice retrieving specific names using RegEx. Get ready to become a regular expression master!

Mastering Regular Expressions