Module: ChronoModel::Adapter::Indexes

Included in:
ChronoModel::Adapter
Defined in:
lib/chrono_model/adapter/indexes.rb

Instance Method Summary collapse

Instance Method Details

#add_temporal_indexes(table, range, options = {}) ⇒ Object

Create temporal indexes for timestamp search.

This index is used by TimeMachine.at, ‘.current` and `.past` to build the temporal WHERE clauses that fetch the state of records at a single point in time.

Parameters:

`table`: the table where to create indexes on
`range`: the tsrange field

Options:

`:name`: the index name prefix, defaults to
         index_{table}_temporal_on_{range / lower_range / upper_range}



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# File 'lib/chrono_model/adapter/indexes.rb', line 21

def add_temporal_indexes(table, range, options = {})
  range_idx, lower_idx, upper_idx =
    temporal_index_names(table, range, options)

  chrono_alter_index(table, options) do
    execute "      CREATE INDEX \#{range_idx} ON \#{table} USING gist ( \#{range} )\n    SQL\n\n    # Indexes used for precise history filtering, sorting and, in history\n    # tables, by UPDATE / DELETE triggers.\n    #\n    execute \"CREATE INDEX \#{lower_idx} ON \#{table} ( lower(\#{range}) )\"\n    execute \"CREATE INDEX \#{upper_idx} ON \#{table} ( upper(\#{range}) )\"\n  end\nend\n"

#add_timeline_consistency_constraint(table, range, options = {}) ⇒ Object

Adds an EXCLUDE constraint to the given table, to assure that no more than one record can occupy a definite segment on a timeline.



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# File 'lib/chrono_model/adapter/indexes.rb', line 50

def add_timeline_consistency_constraint(table, range, options = {})
  name = timeline_consistency_constraint_name(table)
  id   = options[:id] || primary_key(table)

  chrono_alter_constraint(table, options) do
    execute "      ALTER TABLE \#{table} ADD CONSTRAINT \#{name}\n        EXCLUDE USING gist ( \#{id} WITH =, \#{range} WITH && )\n    SQL\n  end\nend\n"

#remove_temporal_indexes(table, range, options = {}) ⇒ Object 



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# File 'lib/chrono_model/adapter/indexes.rb', line 38

def remove_temporal_indexes(table, range, options = {})
  indexes = temporal_index_names(table, range, options)

  chrono_alter_index(table, options) do
    indexes.each {|idx| execute "DROP INDEX #{idx}" }
  end
end

#remove_timeline_consistency_constraint(table, options = {}) ⇒ Object 



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# File 'lib/chrono_model/adapter/indexes.rb', line 62

def remove_timeline_consistency_constraint(table, options = {})
  name = timeline_consistency_constraint_name(table)

  chrono_alter_constraint(table, options) do
    execute "      ALTER TABLE \#{table} DROP CONSTRAINT \#{name}\n    SQL\n  end\nend\n"

#timeline_consistency_constraint_name(table) ⇒ Object 



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# File 'lib/chrono_model/adapter/indexes.rb', line 72

def timeline_consistency_constraint_name(table)
  "#{table}_timeline_consistency"
end