# Key Value Storage
As previously highlighted, the key-value storage mechanism in Cosmos-SDK operates on the premise that each value is stored under a corresponding key.
This storage system is organized within a tree structure, specifically following the cosmos/iavl tree model.
To understand the workings of this key-value storage approach, let's delve into its mechanics:
In order to facilitate your understanding of KV store iterators, let's employ a highly simplified analogy. Imagine letters enclosed within circles, where each letter represents a key, and each key is associated with a corresponding value.
Let's continue by considering a set of saved key-value pairs:
**J** -> value1
**JF** -> value2
**JPV** -> value3
**JPVA** -> value4
**JPVD** -> value5
**JPVX** -> value6
Fetching a Single Value with a Known Key is an Efficient O(1) Operation. However, When Navigating Through a Set of Keys, It's Achieved Through Prefix-Based Iteration.
**J** key, prefixes: **J**
**JF** key, prefixes: **J, JF**
**JPV** key, prefixes: **J,JP, JPV**
**JPVA** key, prefixes: **J,JP, JPV, JPVA**
**JPVD** key, prefixes: **J,JP, JPV, JPVD**
**JPVX** key, prefixes: **J,JP, JPV, JPVX**
range(**J**) returns all keys because all have **J** as prefix range(**JF**) returns only **JF**
\
This is where it gets intriguing.: range(**JPV**) returns **JPV**, **JPVA**, **JPVD**, **JPVX** in order As you can see **J** or **JF** is not returned, because values after JPV is requested.
But Why Was **JPVA** Returned?
The keys stored in the database are in the form of fixed-length strings. For instance, if we assume that keys are uniformly 8 characters in length, the storage representation of "**JPVA**" would be "**JPVA0000**".
When a range request is initiated, the underlying process systematically iterates over all keys within a specific range, starting from "**JPV00000**" and concluding at "**JPVFFFFF**." In this case, "**JPVA**" (among other keys) naturally falls within this range. It's important to note that a range query can also be executed in reverse, offering flexibility in key retrieval.
We have two fundamental operations at play: Retrieving Individual Values and Iterating
There are just two core functionalities in operation: fetching a single value or navigating through a collection of keys. While data structures often require intricate relationships, we work within the confines of this constrained key-value storage, where these two fundamental operations are paramount.
This is accomplished through the construction of indexes.
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