Drops.SQL.Database.PrimaryKey (drops_relation v0.1.0)
View SourceRepresents a primary key constraint in a database table.
This struct stores information about primary key columns, supporting both single-column and composite primary keys. The columns attribute contains the actual Column structs that form the primary key, and meta contains additional information including whether it's a composite key.
Examples
# Single primary key
%Drops.SQL.Database.PrimaryKey{
columns: [%Drops.SQL.Database.Column{name: "id", ...}],
meta: %{composite: false}
}
# Composite primary key
%Drops.SQL.Database.PrimaryKey{
columns: [
%Drops.SQL.Database.Column{name: "user_id", ...},
%Drops.SQL.Database.Column{name: "role_id", ...}
],
meta: %{composite: true}
}
# No primary key
%Drops.SQL.Database.PrimaryKey{
columns: [],
meta: %{composite: false}
}Summary
Functions
Creates a new PrimaryKey struct.
Types
@type meta() :: %{composite: boolean()}
@type t() :: %Drops.SQL.Database.PrimaryKey{ columns: [Drops.SQL.Database.Column.t()], meta: meta() }
Functions
@spec new([Drops.SQL.Database.Column.t()]) :: t()
Creates a new PrimaryKey struct.
Parameters
columns- List of Column structs that form the primary key
Examples
iex> alias Drops.SQL.Database.Column
iex> col = Column.new("id", :integer, %{nullable: false, default: nil, primary_key: true, check_constraints: []})
iex> pk = Drops.SQL.Database.PrimaryKey.new([col])
iex> length(pk.columns)
1
iex> pk.meta.composite
false
iex> alias Drops.SQL.Database.Column
iex> col1 = Column.new("user_id", :integer, %{nullable: false, default: nil, primary_key: true, check_constraints: []})
iex> col2 = Column.new("role_id", :integer, %{nullable: false, default: nil, primary_key: true, check_constraints: []})
iex> pk = Drops.SQL.Database.PrimaryKey.new([col1, col2])
iex> length(pk.columns)
2
iex> pk.meta.composite
true
iex> Drops.SQL.Database.PrimaryKey.new([])
%Drops.SQL.Database.PrimaryKey{columns: [], meta: %{composite: false}}