DbRelation is a DbObject descendant describing a database table like object: a named collection of strictly structured records good to mention in the FROM clause of a SELECT SQL statement, such as:

• DbTable;
• DbView; and, possibly other similar things.

Properties

See DbObject's Properties

Name	Type	Description
columns	{String: DbColumn / null} Object / function	data columns definitions, may be set as a function called with the DbRelation instance available as this
columnsToDrop	[String]	Calculated list of columns with null definition, presumed to be dropped if found existing
pk	[String]	the list of column names composing the primary key
keys	{String: DbIndex} Object	index definitions

Constructor

This class is considered abstract, so the constructor

new DbRelation ({name, columns, pk})

should never be called explicitly.

In the base implementation, it:

• copies all properties from the given argument to this;
• builds DbColumn instances for columns from incoming plain Objects or Strings (parsing DSL);
• if pk came scalar, wraps it into an Array, empty Array for null or undefined pk;
• for each element of pk, sets nullable: false for the eponymous column, or throws an Error if it's not found.