Class: CleanSweep::TableSchema

Inherits:
Object
  • Object
show all
Defined in:
lib/clean_sweep/table_schema.rb

Defined Under Namespace

Classes: ColumnSchema, IndexSchema

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(model, options = {}) ⇒ TableSchema

Returns a new instance of TableSchema.



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# File 'lib/clean_sweep/table_schema.rb', line 15

def initialize(model, options={})

  traversing_key_name  = options[:index]
  ascending            = !options[:reverse]
  first_only           = options[:first_only]
  @model               = model
  @dest_model          = options[:dest_model] || @model

  # Downcase and symbolize the entries in the column name map:
  dest_columns_map     = Hash[*(options[:dest_columns] || {}).to_a.flatten.map{|n| n.to_s.downcase.to_sym}]

  @name                = @model.table_name

  @columns      =
    (options[:copy_columns] || []).map do | extra_col_name |
      CleanSweep::TableSchema::ColumnSchema.new extra_col_name, model
    end

  key_schemas = build_indexes

  # Primary key only supported, but we could probably get around this by adding
  # all columns as 'primary key columns'
  @primary_key = find_primary_key(key_schemas)
  raise "Table #{model.table_name} must have a primary key" unless @primary_key

  @primary_key.add_columns_to @columns
  if !options[:non_traversing]
    if traversing_key_name
      traversing_key_name.downcase!
      raise "BTREE Index #{traversing_key_name} not found in #@name" unless key_schemas.include? traversing_key_name
      @traversing_key = key_schemas[traversing_key_name]
      @traversing_key.add_columns_to @columns
    else
      @traversing_key = @primary_key
    end
    @traversing_key.ascending = ascending
    @traversing_key.first_only = first_only
  end

  # Specify the column names in the destination map, if provided
  @columns.each do | column |
    column.dest_name = dest_columns_map[column.name]
  end

end

Instance Attribute Details

#columns ⇒ Object (readonly)

The list of columns used when selecting, the union of pk and traversing key columns



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# File 'lib/clean_sweep/table_schema.rb', line 5

def columns
  @columns
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/clean_sweep/table_schema.rb', line 13

def name
  @name
end

#primary_key ⇒ Object (readonly)

The schema for the primary key



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# File 'lib/clean_sweep/table_schema.rb', line 8

def primary_key
  @primary_key
end

#traversing_key ⇒ Object (readonly)

The schema for the traversing key, or nil



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# File 'lib/clean_sweep/table_schema.rb', line 11

def traversing_key
  @traversing_key
end

Instance Method Details

#column_names ⇒ Object 



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# File 'lib/clean_sweep/table_schema.rb', line 61

def column_names
  @columns.map(&:name)
end

#delete_statement(rows) ⇒ Object 



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# File 'lib/clean_sweep/table_schema.rb', line 69

def delete_statement(rows)
  rec_criteria = rows.map do | row |
    row_compares = []
    @primary_key.columns.each do |column|
      row_compares << "#{column.quoted_dest_name(@dest_model)} = #{column.quoted_value(row)}"
    end
    "(" + row_compares.join(" AND ") + ")"
  end
  "DELETE FROM #{@dest_model.quoted_table_name} WHERE #{rec_criteria.join(" OR ")}"
end

#first_only? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/clean_sweep/table_schema.rb', line 94

def first_only?
  @traversing_key && @traversing_key.first_only
end

#initial_scope ⇒ Object 



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# File 'lib/clean_sweep/table_schema.rb', line 80

def initial_scope
  scope = @model.select(quoted_column_names).from(from_clause)
  scope = @traversing_key.order(scope) if @traversing_key
  return scope
end

#insert_statement(rows) ⇒ Object 



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# File 'lib/clean_sweep/table_schema.rb', line 65

def insert_statement(rows)
  "insert into #{@dest_model.quoted_table_name} (#{quoted_dest_column_names}) values #{quoted_row_values(rows)}"
end

#scope_to_next_chunk(scope, last_row) ⇒ Object 



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# File 'lib/clean_sweep/table_schema.rb', line 86

def scope_to_next_chunk scope, last_row
  if @traversing_key.blank?
    scope
  else
    @traversing_key.scope_to_next_chunk(scope, last_row)
  end
end