Class: DeclareSchema::Model::IndexDefinition

Inherits:
Object
  • Object
show all
Includes:
Comparable
Defined in:
lib/declare_schema/model/index_definition.rb

Defined Under Namespace

Classes: IndexNameTooLongError

Constant Summary collapse

OPTIONS = 
[:name, :unique, :where, :length].freeze
PRIMARY_KEY_NAME = 
"PRIMARY"

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(columns, table_name:, name: nil, allow_equivalent: false, unique: false, where: nil, length: nil) ⇒ IndexDefinition

Returns a new instance of IndexDefinition.



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# File 'lib/declare_schema/model/index_definition.rb', line 19

def initialize(columns, table_name:, name: nil, allow_equivalent: false, unique: false, where: nil, length: nil)
  @table_name = table_name
  @name = (name || self.class.default_index_name(table_name, columns)).to_s
  @columns = Array.wrap(columns).map(&:to_s)
  @explicit_name = @name if !allow_equivalent
  unique.in?([false, true]) or raise ArgumentError, "unique must be true or false: got #{unique.inspect}"
  if @name == PRIMARY_KEY_NAME
    unique or raise ArgumentError, "primary key index must be unique"
  end
  @unique = unique

  if DeclareSchema.max_index_and_constraint_name_length && @name.length > DeclareSchema.max_index_and_constraint_name_length
    raise IndexNameTooLongError, "Index '#{@name}' exceeds configured limit of #{DeclareSchema.max_index_and_constraint_name_length} characters. Give it a shorter name, or adjust DeclareSchema.max_index_and_constraint_name_length if you know your database can accept longer names."
  end

  if where
    @where = where.start_with?('(') ? where : "(#{where})"
  end

  @length = self.class.normalize_index_length(length, columns: @columns)
end

Class Method Details

.default_index_name(table_name, columns) ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 66

def default_index_name(table_name, columns)
  index_name = nil
  [:long_index_name, :short_index_name].find do |method_name|
    index_name = send(method_name, table_name, columns)
    if DeclareSchema.max_index_and_constraint_name_length.nil? || index_name.length <= DeclareSchema.max_index_and_constraint_name_length
      break index_name
    end
  end or raise IndexNameTooLongError,
               "Default index name '#{index_name}' exceeds configured limit of #{DeclareSchema.max_index_and_constraint_name_length} characters. Use the `name:` option to give it a shorter name, or adjust DeclareSchema.max_index_and_constraint_name_length if you know your database can accept longer names."
end

.for_table(table_name, ignore_indexes, connection) ⇒ Object

extract IndexSpecs from an existing table includes the PRIMARY KEY index



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# File 'lib/declare_schema/model/index_definition.rb', line 44

def for_table(table_name, ignore_indexes, connection)
  primary_key_columns = Array(connection.primary_key(table_name))
  primary_key_columns.present? or raise "could not find primary key for table #{table_name} in #{connection.columns(table_name).inspect}"

  primary_key_found = false
  index_definitions = connection.indexes(table_name).map do |index|
    next if ignore_indexes.include?(index.name)

    if index.name == PRIMARY_KEY_NAME
      index.columns == primary_key_columns && index.unique or
        raise "primary key on #{table_name} was not unique on #{primary_key_columns} (was unique=#{index.unique} on #{index.columns})"
      primary_key_found = true
    end
    new(index.columns, name: index.name, table_name: table_name, unique: index.unique, where: index.where, length: index.lengths)
  end.compact

  if !primary_key_found
    index_definitions << new(primary_key_columns, name: PRIMARY_KEY_NAME, table_name: table_name, unique: true)
  end
  index_definitions
end

.normalize_index_length(length, columns:) ⇒ Hash<Symbol, nil>

This method normalizes the length option to be either nil or a Hash of Symbol column names to lengths, so that we can safely compare what the user specified with what we get when querying the database schema.

Returns:

  • (Hash<Symbol, nil>) 


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# File 'lib/declare_schema/model/index_definition.rb', line 80

def normalize_index_length(length, columns:)
  case length
  when nil, {}
    nil
  when Integer
    if columns.size == 1
      { columns.first.to_sym => length }
    else
      raise ArgumentError, "Index length of Integer only allowed when exactly one column; got #{length.inspect} for #{columns.inspect}"
    end
  when Hash
    length.transform_keys(&:to_sym)
  else
    raise ArgumentError, "Index length must be nil or Integer or a Hash of column names to lengths; got #{length.inspect} for #{columns.inspect}"
  end
end

Instance Method Details

#<=>(rhs) ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 151

def <=>(rhs)
  to_key <=> rhs.to_key
end

#equivalent?(rhs) ⇒ Boolean

Returns:



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# File 'lib/declare_schema/model/index_definition.rb', line 155

def equivalent?(rhs)
  settings == rhs.settings
end

#hash ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 147

def hash
  to_key.hash
end

#options ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 130

def options
  @options ||=
    OPTIONS.each_with_object({}) do |option, result|
      result[option] = send(option)
    end.freeze
end

#primary_key? ⇒ Boolean

Returns:



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# File 'lib/declare_schema/model/index_definition.rb', line 126

def primary_key?
  name == PRIMARY_KEY_NAME
end

#settings ⇒ Object

The index settings for this object. Used for equivalence checking. Does not include the name.



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# File 'lib/declare_schema/model/index_definition.rb', line 143

def settings
  @settings ||= [columns, options.except(:name)].freeze
end

#to_key ⇒ Object

Unique key for this object. Used for equality checking.



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# File 'lib/declare_schema/model/index_definition.rb', line 138

def to_key
  @to_key ||= [name, *settings].freeze
end

#with_name(new_name) ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 159

def with_name(new_name)
  self.class.new(@columns, name: new_name, table_name: @table_name, unique: @unique, allow_equivalent: @explicit_name.nil?, where: @where, length: @length)
end