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

PRIMARY_KEY_NAME = 
"PRIMARY"
MYSQL_INDEX_NAME_MAX_LENGTH = 
64

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(model, fields, options = {}) ⇒ IndexDefinition

Returns a new instance of IndexDefinition.



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# File 'lib/declare_schema/model/index_definition.rb', line 17

def initialize(model, fields, options = {})
  @model = model
  @table = options.delete(:table_name) || model.table_name
  @fields = Array.wrap(fields).map(&:to_s)
  @explicit_name = options[:name] unless options.delete(:allow_equivalent)
  @name = options.delete(:name) || self.class.index_name(@fields)
  @unique = options.delete(:unique) || name == PRIMARY_KEY_NAME || false

  if @name.length > MYSQL_INDEX_NAME_MAX_LENGTH
    raise IndexNameTooLongError, "Index '#{@name}' exceeds MySQL limit of #{MYSQL_INDEX_NAME_MAX_LENGTH} characters. Give it a shorter name."
  end

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

Instance Attribute Details

#explicit_name ⇒ Object (readonly)

TODO: replace fields with columns and remove alias. -Colin



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# File 'lib/declare_schema/model/index_definition.rb', line 9

def explicit_name
  @explicit_name
end

#fields ⇒ Object (readonly) Also known as: columns

TODO: replace fields with columns and remove alias. -Colin



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# File 'lib/declare_schema/model/index_definition.rb', line 9

def fields
  @fields
end

#name ⇒ Object (readonly)

TODO: replace fields with columns and remove alias. -Colin



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# File 'lib/declare_schema/model/index_definition.rb', line 9

def name
  @name
end

#table ⇒ Object (readonly)

TODO: replace fields with columns and remove alias. -Colin



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# File 'lib/declare_schema/model/index_definition.rb', line 9

def table
  @table
end

#unique ⇒ Object (readonly)

TODO: replace fields with columns and remove alias. -Colin



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# File 'lib/declare_schema/model/index_definition.rb', line 9

def unique
  @unique
end

#where ⇒ Object (readonly)

TODO: replace fields with columns and remove alias. -Colin



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# File 'lib/declare_schema/model/index_definition.rb', line 9

def where
  @where
end

Class Method Details

.for_model(model, old_table_name = nil) ⇒ Object

extract IndexSpecs from an existing table always includes the PRIMARY KEY index



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# File 'lib/declare_schema/model/index_definition.rb', line 37

def for_model(model, old_table_name = nil)
  t = old_table_name || model.table_name

  primary_key_columns = Array(model.connection.primary_key(t)).presence || sqlite_compound_primary_key(model, t) or
    raise "could not find primary key for table #{t} in #{model.connection.columns(t).inspect}"

  primary_key_found = false
  index_definitions = model.connection.indexes(t).map do |i|
    model.ignore_indexes.include?(i.name) and next
    if i.name == PRIMARY_KEY_NAME
      i.columns == primary_key_columns && i.unique or
        raise "primary key on #{t} was not unique on #{primary_key_columns} (was unique=#{i.unique} on #{i.columns})"
      primary_key_found = true
    elsif i.columns == primary_key_columns && i.unique
      # skip this primary key index since we'll create it below, with PRIMARY_KEY_NAME
      next
    end
    new(model, i.columns, name: i.name, unique: i.unique, where: i.where, table_name: old_table_name)
  end.compact

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

.index_name(columns) ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 63

def index_name(columns)
  "on_#{Array(columns).join("_and_")}"
end

Instance Method Details

#<=>(rhs) ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 127

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 131

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

#hash ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 123

def hash
  to_key.hash
end

#primary_key? ⇒ Boolean

Returns:



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# File 'lib/declare_schema/model/index_definition.rb', line 92

def primary_key?
  name == PRIMARY_KEY_NAME
end

#settings ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 119

def settings
  @settings ||= [table, fields, unique].map(&:to_s)
end

#to_add_primary_key_statement(new_table_name, existing_primary_key) ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 109

def to_add_primary_key_statement(new_table_name, existing_primary_key)
  drop = "DROP PRIMARY KEY, " if existing_primary_key
  statement = "ALTER TABLE #{new_table_name} #{drop}ADD PRIMARY KEY (#{fields.join(', ')})"
  "execute #{statement.inspect}"
end

#to_add_statement(new_table_name, existing_primary_key = nil) ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 96

def to_add_statement(new_table_name, existing_primary_key = nil)
  if primary_key? && !ActiveRecord::Base.connection.class.name.match?(/SQLite3Adapter/)
    to_add_primary_key_statement(new_table_name, existing_primary_key)
  else
    # Note: + below keeps that interpolated string from being frozen, so we can << into it.
    r = +"add_index #{new_table_name.to_sym.inspect}, #{fields.map(&:to_sym).inspect}"
    r << ", unique: true"      if unique
    r << ", where: '#{where}'" if where.present?
    r << ", name: '#{name}'"
    r
  end
end

#to_key ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 115

def to_key
  @key ||= [table, fields, name, unique, where].map(&:to_s)
end

#with_name(new_name) ⇒ Object 



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# File 'lib/declare_schema/model/index_definition.rb', line 135

def with_name(new_name)
  self.class.new(@model, @fields, table_name: @table_name, index_name: @index_name, unique: @unique, name: new_name)
end