Class: Exwiw::TableConfig

Inherits:
Object
  • Object
show all
Includes:
Serdes
Defined in:
lib/exwiw/table_config.rb

Constant Summary collapse

RAILS_MANAGED_SCHEMA_MIGRATIONS = 
"rails_managed_schema_migrations"
RAILS_MANAGED_INTERNAL_METADATA = 
"rails_managed_internal_metadata"
RAILS_MANAGED_TYPES = 
[
  RAILS_MANAGED_SCHEMA_MIGRATIONS,
  RAILS_MANAGED_INTERNAL_METADATA,
].freeze
UNSUPPORTED_COMPOSITE_PRIMARY_KEY =

type marking a table with a composite primary key, which exwiw does not support yet. schema:generate attaches it together with ignore:true. Unlike rails-managed tables, columns/belongs_tos are retained so it can serve as a signpost for adding support later.

"unsupported_composite_primary_key"

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.from(hash) ⇒ Object 



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# File 'lib/exwiw/table_config.rb', line 30

def self.from(hash)
  config = super
  config.send(:validate_after_load!)
  config
end

.from_symbol_keys(hash) ⇒ Object 



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# File 'lib/exwiw/table_config.rb', line 36

def self.from_symbol_keys(hash)
  from(JSON.parse(hash.to_json))
end

Instance Method Details

#belongs_to(table_name) ⇒ Object 



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# File 'lib/exwiw/table_config.rb', line 81

def belongs_to(table_name)
  belongs_tos.find { |relation| relation.table_name == table_name }
end

#build_extract_query(extract_target_table, extract_target_ids, tables_by_name) ⇒ Object 



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# File 'lib/exwiw/table_config.rb', line 85

def build_extract_query(extract_target_table, extract_target_ids, tables_by_name)
  # target is itself
  if name == extract_target_table
    return [{
      from: name,
      where: [{ primary_key => extract_target_ids }],
      join: [],
      select: column_names,
    }]
  end

  # it is not related to target table
  if belongs_to.empty?
    return [{
      from: name,
      where: [],
      join: [],
      select: column_names,
    }]
  end

  belongs_to_extract_target_table = belongs_tos.find { |relation| relation.table_name == extract_target_table }
  if belongs_to_extract_target_table
    key = belongs_to_extract_target_table.foreign_key
    return [{ from: name, where: [{ key => extract_target_ids }], join: [], select: column_names }]
  end

  ret = compute_dependency_to_table(extract_target_table, tables_by_name)

  if ret.empty?
    [{
      from: name,
      where: [],
      join: [],
      select: column_names,
    }]
  else
    last = ret.last
    last[:where] = [{ last[:foreign_key] => extract_target_ids }]
    ret
  end
end

#column_names ⇒ Object 



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# File 'lib/exwiw/table_config.rb', line 53

def column_names
  columns.map(&:name)
end

#merge(passed_table) ⇒ Object 



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# File 'lib/exwiw/table_config.rb', line 128

def merge(passed_table)
  return passed_table if passed_table.to_hash == self.to_hash


  TableConfig.new.tap do |merged_table|
    merged_table.name = name
    merged_table.primary_key = passed_table.primary_key
    merged_table.type = passed_table.type
    merged_table.comment = comment
    merged_table.filter = filter
    merged_table.bulk_insert_chunk_size = passed_table.bulk_insert_chunk_size
    merged_table.ignore = ignore

    # Structural facts of each belongs_to come from the freshly generated
    # config, but the user-owned `comment`/`ignore` carry over when the same
    # relation still exists.
    receiver_belongs_to_by_identity = belongs_tos.each_with_object({}) { |bt, hash| hash[bt.identity] = bt }
    merged_table.belongs_tos =
      passed_table.belongs_tos.map do |passed_belongs_to|
        receiver_belongs_to = receiver_belongs_to_by_identity[passed_belongs_to.identity]
        if receiver_belongs_to
          passed_belongs_to.comment = receiver_belongs_to.comment if receiver_belongs_to.comment
          passed_belongs_to.ignore = receiver_belongs_to.ignore unless receiver_belongs_to.ignore.nil?
        end
        passed_belongs_to
      end

    receiver_column_by_name = columns.each_with_object({}) { |column, hash| hash[column.name] = column }

    merged_table.columns =
      passed_table.columns.map do |passed_column|
        if receiver_column_by_name.key?(passed_column.name)
          receiver_column = receiver_column_by_name[passed_column.name]
          receiver_column
        else
          passed_column
        end
      end
  end
end

#rails_managed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/exwiw/table_config.rb', line 40

def rails_managed?
  RAILS_MANAGED_TYPES.include?(type)
end

#reject_ignored_members! ⇒ Object

Drop the belongs_tos/columns flagged ‘ignore:true` so they are excluded from extraction (dependency ordering, SELECT projection, INSERT). The config files on disk keep these entries; this is applied to the runtime config right after it is loaded from a file (see Runner#load_table_config).



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# File 'lib/exwiw/table_config.rb', line 61

def reject_ignored_members!
  self.belongs_tos = belongs_tos.reject(&:ignore)
  self.columns = columns.reject(&:ignore)

  # A table that will be extracted needs at least one effective column;
  # otherwise the generated SELECT (`SELECT  FROM ...`) and INSERT
  # (`INSERT INTO t () ...`) are syntactically broken. Checked here, after
  # rejection, so it catches both a genuinely empty `columns: []` and a list
  # left empty because every column was ignore:true. Schema generation does
  # not call this method, so regenerating a broken config still works.
  if !rails_managed? && !ignore && columns.empty?
    raise ArgumentError,
          "Table '#{name}' has no columns to extract " \
          "(it may be empty in the config or have all columns set to ignore:true); " \
          "define or unignore at least one column."
  end

  self
end

#to_hash ⇒ Object 



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# File 'lib/exwiw/table_config.rb', line 44

def to_hash
  hash = super
  if rails_managed?
    hash.delete("belongs_tos")
    hash.delete("columns")
  end
  hash
end