Class: SlashMigrate::AddColumnsMigration

Inherits:
Object
  • Object
show all
Defined in:
app/services/slash_migrate/add_columns_migration.rb

Overview

Builds a migration that adds one or more columns to an existing table. add_column / add_reference are reversible, so this stays a plain def change.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(table:, columns: []) ⇒ AddColumnsMigration

Returns a new instance of AddColumnsMigration.



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# File 'app/services/slash_migrate/add_columns_migration.rb', line 21

def initialize(table:, columns: [])
  @table = table.to_s
  @columns = columns.reject(&:blank?)
end

Instance Attribute Details

#table ⇒ Object (readonly)

Returns the value of attribute table.



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# File 'app/services/slash_migrate/add_columns_migration.rb', line 19

def table
  @table
end

Class Method Details

.from_params(table:, rows:) ⇒ Object 



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# File 'app/services/slash_migrate/add_columns_migration.rb', line 5

def self.from_params(table:, rows:)
  columns = Array(rows).map { |row| Column.from_params(resolve_self_reference(row, table)) }
  new(table: table, columns: columns)
end

.resolve_self_reference(row, table) ⇒ Object

A self-reference here points at the table being modified, which already exists. Reuse the create-table sentinel so the shared row partial works.



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# File 'app/services/slash_migrate/add_columns_migration.rb', line 12

def self.resolve_self_reference(row, table)
  return row unless row[:to_table].to_s == MigrationBuilder::SELF_TABLE

  hash = row.respond_to?(:to_unsafe_h) ? row.to_unsafe_h : row.to_h
  hash.symbolize_keys.merge(to_table: table)
end

Instance Method Details

#any? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'app/services/slash_migrate/add_columns_migration.rb', line 26

def any?
  @columns.any?
end

#migration_basename ⇒ Object 



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# File 'app/services/slash_migrate/add_columns_migration.rb', line 38

def migration_basename
  @columns.one? ? "add_#{@columns.first.name}_to_#{@table}" : "add_columns_to_#{@table}"
end

#migration_class_name ⇒ Object 



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# File 'app/services/slash_migrate/add_columns_migration.rb', line 30

def migration_class_name
  if @columns.one?
    "Add#{@columns.first.name.camelize}To#{@table.camelize}"
  else
    "AddColumnsTo#{@table.camelize}"
  end
end

#migration_source ⇒ Object 



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# File 'app/services/slash_migrate/add_columns_migration.rb', line 42

def migration_source
  lines = []
  lines << "class #{migration_class_name} < ActiveRecord::Migration[#{ActiveRecord::Migration.current_version}]"
  lines << "  def change"
  @columns.each do |column|
    lines << "    #{column.add_statement(@table)}"
    lines << "    #{column.index_statement(@table)}" if column.indexed?
  end
  lines << "  end"
  lines << "end"
  lines.join("\n") + "\n"
end

#write! ⇒ Object 



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# File 'app/services/slash_migrate/add_columns_migration.rb', line 55

def write!
  [MigrationFileWriter.write(basename: migration_basename, source: migration_source)]
end