# groonga - An open-source fulltext search engine and column store.

- 日本語版はこちら

# 7.6. Column

Column is a data store object or an index object for fast search.

A column belongs to a table. Table has zero or more columns.

Both data store column and index column have type. Type of data store column specifies data range. In other words, it is "value type". Type of index column specifies set of documents to be indexed. A set of documents is a table in Groonga. In other words, type of index column must be a table.

Here are data store columns:

> - `columns/scalar`
> - Vector column
> - 疑似カラム (pseudo_column)

Here is an index column:

> - `columns/index`