---
title: "Naming rules"
sidebarTitle: "Naming Rules"
description: "The names a database, namespace, table or view can have, and which versions check them."
icon: signature
keywords: ["names", "naming", "table name", "namespace name", "identifier", "characters", "limits"]
---

A name ends up in a storage path, in a deployment's URLs, and in the identifiers
that [authorization](/governance/authorization) records, so not every string
works as one. A name that follows the rules on this page works on every
connection. Some connections accept more today, as
[below](#which-versions-check-them), but treat these rules as the contract.

## The rules {#rules}

| Object | Characters | Length |
| --- | --- | --- |
| Table, materialized view | ASCII letters and digits, `-`, `_`, `.` | 1 to 128 characters |
| View | ASCII letters and digits, `-`, `_`, `.` | 1 to 128 characters |
| Namespace | each component: ASCII letters and digits, `-`, `_`, `.` | 1 to 64 characters a component; at most 10 components |
| Database | ASCII letters and digits, `-`, `_`, `.`, and `/` between components | up to 64 characters |
| Branch | anything but `$` and `:` | 1 to 64 characters |
| Secret | ASCII letters and digits, `-`, `_`, `.` | 1 to 128 characters |
| Function {/* if functions launched */} | ASCII letters and digits, `_` -- no `-` or `.` | 1 to 128 characters |

And for every name:

- It can't be empty, and neither can any component of a namespace path or a
  database name.
- It can't be `.` or `..`, nor can any of its components.
- A namespace path whose first component is `public` can't have a second one.

`$` and `:` are never in a name: a deployment writes a namespace path and a
table as one identifier joined by `$`, and a database and a table, or a table
and a branch, joined by `:`.

## Examples {#examples}

| Name | |
| --- | --- |
| `documents`, `user-events.v2`, `train_2026` | valid table names |
| `["prod", "search"]` | a valid two-component namespace path |
| `my table` | refused: a space |
| `orders$2026` | refused: `$` joins a namespace and a table |
| `résumés` | refused: not ASCII |
| `["public", "search"]` | refused: `public` can't have a child |

## Which versions check them {#which-versions-check-them}

The rules come from lancedb
[#4490](https://github.com/lancedb/lancedb/pull/4490), which gives the SDKs and
deployments one set of name checks. What enforces them depends on the
connection and the version:

- **The embedded library** refuses a table name with any other character, and
  `.` and `..`, but sets no length limit beyond what the filesystem allows. A
  directory namespace accepts other characters in namespace names.
- **The SDKs on a `db://` connection** check every name above before sending a
  request, from the first release that includes #4490. As of v0.41.0-beta.2, no
  release does: earlier releases send names to the deployment unchecked.
- **A deployment** checks names itself, but not on every path in every version.
  Some accept a longer name when a table is created and then fail on it later --
  when the table is dropped, or in background work on it.

So keep to the rules even where a longer or unusual name is accepted: a name
that works today on one connection can fail on another, or later on the same
one.

See [Limits](/basics/limits#names) for the other bounds, and
[Namespaces](/management/namespace#namespace-paths-and-names) for how a path is
built.