LanguageTable constraints

Table constraints

Some facts span several columns. Write them as a line of their own inside the table block.

table orders {
  id  bigint  pk
}

table order_items {
  id          bigint  pk
  order_id    bigint  -> orders
  product_id  bigint
  unique(order_id, product_id) as uk_order_product
  index(product_id, order_id)
}

The diagram resin draws for order_items.erd

Constraint	Meaning
`unique(a, b)`, `unique(a, b) as name`	A composite UNIQUE
`index(a, b)`, `index(a, b) as name`	A composite index

Every column in the list must exist in the table. For a single column, use the column modifiers uk and index; a constraint over one column is reported as a warning.

A column called index

A constraint starts only when ( follows the keyword directly. So index int is a column named index, while index(a, b) is a constraint:

table jobs {
  id     bigint  pk
  index  int     "Position in the queue"
}

Keywords in resin are never reserved; see Names and comments.

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Table constraints

A column called index#

A column called index