---
title: "Table inheritance"
url: "https://docs.yugabyte.com/stable/api/ysql/the-sql-language/ddl-inherit/"
---

# Table inheritance

How INHERITS works in YSQL, including columns, constraints, queries, schema changes, and limitations.

YSQL supports table inheritance with the `INHERITS` clause of [CREATE TABLE](/stable/api/ysql/the-sql-language/statements/ddl_create_table/ "CREATE TABLE"). A child table inherits columns and certain constraints from one or more parent tables. For the allowed differences between a parent column and a child column, and how those differences are resolved, see the [PostgreSQL documentation](https://www.postgresql.org/docs/15/ddl-inherit.html "PostgreSQL documentation").

For an accounts schema that uses `INHERITS`, see [Table inheritance example](/stable/explore/ysql-language-features/advanced-features/inheritance/ "Table inheritance example").



## What a child inherits

Columns, column defaults, check constraints, and not-null constraints propagate from a parent to its children. A check constraint marked `NO INHERIT` stays on the parent only.

Primary keys, unique constraints, indexes, and foreign keys do not propagate. Define them on each child.

A table can inherit from more than one parent, and a child can itself be a parent. The parent can also contain rows that are not in any child.

## Queries and updates

`SELECT`, `UPDATE`, and `DELETE` on a parent operate on the parent and every child. `ONLY` restricts the statement to the named table. `INSERT` always inserts into the named table only; rows inserted into a parent aren't routed to a child. For an example that uses `ONLY`, see [Queries and updates on data](/stable/explore/ysql-language-features/advanced-features/inheritance/#queries-and-updates-on-data "Queries and updates on data").

## Schema changes

Adding, dropping, or altering a column on the parent propagates to every child. The result is more complex when a child already has a column of the same name and type, or inherits that column from more than one parent with differing definitions, such as `NULL` versus `NOT NULL`.

Adding or dropping a check constraint propagates to every child. Adding or dropping a primary key, unique constraint, or foreign key does not.

`ONLY` restricts some schema changes to the parent. `ALTER TABLE ONLY accounts DROP COLUMN profit` drops the column on `accounts` and leaves it on the children.

## Limitations

- Dropping or adding a column on a parent fails when a local column of that name exists on a child. [#26094](https://github.com/yugabyte/yugabyte-db/issues/26094)
- Obtaining a row lock on a parent crashes when a child is a `file_fdw` table. [#27105](https://github.com/yugabyte/yugabyte-db/issues/27105)

For an up-to-date list, see [#27949](https://github.com/yugabyte/yugabyte-db/issues/27949).