---
title: "25: Defining indexes | SurrealDB University"
description: "Follow along with interactive SurrealDB lessons featuring hands-on exercises, code examples, and step-by-step instructions."
url: https://surrealdb.com/learn/tour/page-25
---

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[Welcome to the Tour of SurrealDB!](https://surrealdb.com/learn/tour) [1: Connecting to a database](https://surrealdb.com/learn/tour/page-01) [2: Creating records](https://surrealdb.com/learn/tour/page-02) [3: Using the ONLY keyword](https://surrealdb.com/learn/tour/page-03) [4: Non-ASCII record IDs](https://surrealdb.com/learn/tour/page-04) [5: Parentheses, indexing, and accessing fields](https://surrealdb.com/learn/tour/page-05) [6: Deleting records](https://surrealdb.com/learn/tour/page-06) [7: Field order in objects](https://surrealdb.com/learn/tour/page-07) [8: Tips when selecting records](https://surrealdb.com/learn/tour/page-08) [9: Casting and aliases](https://surrealdb.com/learn/tour/page-09) [10: Affixes](https://surrealdb.com/learn/tour/page-10) [11: Updating records](https://surrealdb.com/learn/tour/page-11) [12: Linking records](https://surrealdb.com/learn/tour/page-12) [13: Viewing the database as a whole](https://surrealdb.com/learn/tour/page-13) [14: Schemafull and schemaless](https://surrealdb.com/learn/tour/page-14) [15: Viewing the schema](https://surrealdb.com/learn/tour/page-15) [16: Literal types and assertions](https://surrealdb.com/learn/tour/page-16) [17: INSERT and using JSON](https://surrealdb.com/learn/tour/page-17) [18: FOR loops](https://surrealdb.com/learn/tour/page-18) [19: Basic graph relations](https://surrealdb.com/learn/tour/page-19) [20: Creating graph edges](https://surrealdb.com/learn/tour/page-20) [21: Querying graph relations](https://surrealdb.com/learn/tour/page-21) [22: Graph relations at greater depth](https://surrealdb.com/learn/tour/page-22) [23: Adding and improving data](https://surrealdb.com/learn/tour/page-23) [24: Defining events](https://surrealdb.com/learn/tour/page-24) [25: Defining indexes](https://surrealdb.com/learn/tour/page-25) [26: Improving the schema](https://surrealdb.com/learn/tour/page-26) [27: Visualising graph paths](https://surrealdb.com/learn/tour/page-27) [28: Recursive queries: setup](https://surrealdb.com/learn/tour/page-28) [29: Recursive queries](https://surrealdb.com/learn/tour/page-29) [30: More on recursive queries](https://surrealdb.com/learn/tour/page-30) [31: AI vector search](https://surrealdb.com/learn/tour/page-31) [Done the tour!](https://surrealdb.com/learn/tour/page-32)

# 25: Defining indexes

[Indexes](https://surrealdb.com/docs/reference/query-language/statements/define/indexes) can be defined in SurrealDB for a number of ways. The main reason for an index is faster data retrieval. This is used most often when you need to use the `WHERE` clause in a query, which results in a full table scan. But with an index, this is much faster.

```
CREATE person SET name = "Billy";-- Create 25000 more records, each with a random string for a nameCREATE |person:25000| SET name = rand::string(10) RETURN NONE;-- Lots of 'person' records to look through...SELECT * FROM person WHERE name = "Billy";-- Add an indexDEFINE INDEX name_index ON person FIELDS name;-- The same query is much faster nowSELECT * FROM person WHERE name = "Billy";
```

![Surrealist Icon](https://surrealdb.com/assets/static/fdfe2c20f5941d5e.D0guSOhZ.webp) Run Query

Our database has nowhere near 25,000 records so an index for faster lookup times won't be necessary at this point. However, an index has other uses such as being able to ensure that records are unique. To do this, just add the keyword `UNIQUE` to the end.

One place we can use a unique index is the `address` field on the `place` table.

```
DEFINE INDEX unique_address ON TABLE place FIELDS address UNIQUE;CREATE place SET    name = "Wrong house",    address = "2025 Statement Street, Riverdale",    place_type = "building";
```

![Surrealist Icon](https://surrealdb.com/assets/static/fdfe2c20f5941d5e.D0guSOhZ.webp) Run Query

Response

```surql
"Database index `unique_address` already contains
'2025 Statement Street, Riverdale', with record `place:surreal_library`"
```

A unique field can be defined on multiple fields too, such as this one defined on the `in` and `out` fields of a graph edge. This is used quite often to make sure that a `RELATE` statement can't be used more than once on the same two records.

```
DEFINE INDEX can_only_like_once ON TABLE likes FIELDS in, out UNIQUE;RELATE person:one->likes->person:two;RELATE person:one->likes->person:two;
```

![Surrealist Icon](https://surrealdb.com/assets/static/fdfe2c20f5941d5e.D0guSOhZ.webp) Run Query

Response

```surql
'Database index `can_only_like_once` already contains
[person:one, person:two], with record `likes:6lx7cqzesfh9jkic60c2`'
```

Previous

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Next lesson

26: Improving the schema

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