Gain insights into Redis's capabilities as a database, cache, and message broker. Delve into commands, transactions, and clustering. Explore flexibility, security, and data structure support with Redis.

Redis.tar.gz

Redis is an open-source, in-memory data structure store used as a database, cache, and message broker. Unlike Memcached, it supports multiple data types, giving a lot of flexibility to the user. Redis is easy to configure and provides clustering support to store data in multiple servers.

In this course, you will learn about the various commands that you can use to store different types of data structures in Redis. Some of those commands include utility, insertion, and modification commands.

You will also become familiar with different aspects of Redis, such as transactions, security, partitioning, and clustering. In all, this is your go-to guide to Redis.

Complete Guide to Redis

The simplest form of data that can be stored in the Redis database is String. We can store static HTML pages in the Redis database where the key is some name used to identify the page and value is the HTML String. We will look at all the commands used to store and fetch records from the Redis database when the value type is String.
> Please practice all the commands in the terminal at the end of this lesson.

# `SET` command

We can store a record in Redis using the `SET` command. The syntax of this command is:
> SET *key value*

Let's say we need to save the name of a company and its stock price in Redis. In the example below, we are storing the stock price of **Apple** in Redis. When we execute a command in Redis, OK is returned, which means that the command was executed successfully.

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/6685402472644608)






# `GET` command

We can get the stock value of **Apple** using the `GET` command.
> GET *key*

In the example below, we are getting the stock price of **Apple**.

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/6539974880002048)

If we run the `SET` command again for **Apple**, with a different value, then the record in Redis is updated.

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/5835617423327232)

# `SETEX` command

This command is used if we need to set a certain time after which the key will be removed from the database. The time provided is in seconds.

>SETEX *key seconds value*

In the example below, we are storing the stock price for Microsoft. We are providing the time as 40 seconds. When we try to get this key before 40 seconds, then we get the data. We will try again after 40 seconds, and the data will not be returned. The two GET commands demonstrate this case.

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/4912989728669696)

Instead of using the `SETEX` command, we can also use the `SET` command with the `EX` option as shown below.

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/5999861401911296)

# `PSETEX` command

This command is similar to `SETEX` command. The only difference is that the time provided is in milliseconds.
> PSETEX *key millisecond value*

In the example below, we are storing the stock price of Amazon with 20,000 milliseconds as the expiry time.

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/6426679695114240)


Instead of using the `PSETEX` command, we can also use the `SET` command with the `PX` option as shown below.

> SET *key value* PX *milliseconds*







Please try these commands in the terminal below:


* `SET Apple 300`
* `GET Apple`
* `SETEX Microsoft 40 145`
* `PSETEX Amazon 2000 245`


# `SETNX` command

The `SETNX` command is used if a key is already present. If a key is already present and we run `SET` again, then the value is updated. If we need to avoid this, we can use `SETNX`. The syntax of this command is:
> SETNX *key value*

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/5713434193690624)

Instead of using the `SETNX` command, we can use the `SET` command with the `NX` option.

In the example below, the stock price of **apple** is already available in the database. We can set it again with the `NX` option so that the value is not updated.

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/6488291537846272)

# `STRLEN` command
This command is used if we need to find the length of the value for a particular key. The syntax of this command is:
>STRLEN *key*

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/5646065215733760)

# `MSET` command

If we need to save multiple records in a single command, we can use the `MSET` command. In the example below, we are setting the stock prices of multiple companies in a single command. The syntax of this command is:
> MSET *key1 value1 key2 value2*

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/5066539238686720)

# `MGET` command

If we need to get the value of multiple keys in a single command, we can use the `MGET` command. In the example below, we are getting the stock prices of multiple companies in a single command.
> MGET *key1 key2* 

![](/api/collection/6650775272947712/6601946975698944/page/6141570303655936/image/5652222990876672)

Please try these commands in the terminal below:



* `SET Apple 300`
* `GET Apple`
* `SETNX Apple 240 (this will not update the value of Apple)`
* `STRLEN Apple`
* `MSET Google 450 fiserv 230`
* `MGET Google fiserv`


Learn about how we can store Strings in Redis.

Let's Begin

Redis Commands

Redis Advanced Concepts

Redis Cluster

Appendix

Storing Strings in Redis: Insertion and Retrieval Commands