PostgreSQL 中是否有可用的多值字段类型？

Question

I want to know if it is possible to store multiple values in a field in PostgreSQL.

I have a table called Token with the columns id , text and category . category is a multivalued field. Is it necessary to create a separate table for it or is there a way to store it in the Token table?

Answer 1

There are arrays in PostgreSQL. For example:

CREATE TABLE "token" (
  "id"       integer PRIMARY KEY,
  "text"     text,
  "category" text[]
);

Now you can insert multiple categories for each row into token :

INSERT INTO "token" ("id", "text", "category")
VALUES (1, 'some text', ARRAY['cate1', 'cate2']);

You can find the rows like:

SELECT * FROM "token" WHERE 'cate1' = ANY ("category");

Answer 2

There are several:

• arrays
• hstore (associative tables)
• composite types (similar to structs in C, more or less)

Answer 3

I know that this question had been asked 10 years ago but since Postgres is evolving there are new types that are optimized and could be used to address this issue

1. json
2. jsonb aka binary json