Class: Arc::DataStores::AbstractDataStore

Inherits:
ResourcePool
  • Object
show all
Includes:
Casting, ArelCompatibility, Quoting
Defined in:
lib/arc/data_stores/abstract/store.rb

Constant Summary

Constants included from Casting

Casting::CAST_METHODS, Casting::TYPES

Instance Method Summary collapse

Methods included from Casting

#cast

Methods included from Quoting

#quote, #quote_column, #quote_table

Methods included from ArelCompatibility

#columns_hash, #connection, #connection_pool, #primary_key, #quote_hash, #spec, #table_exists?, #visitor, #with_connection

Instance Method Details

#[](table) ⇒ Object Also known as: columns 



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# File 'lib/arc/data_stores/abstract/store.rb', line 13

def [] table
  schema[table]
end

#create(stmt) ⇒ Object 



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# File 'lib/arc/data_stores/abstract/store.rb', line 30

def create stmt
  case stmt
  when String
    execute stmt
  when Arel::InsertManager
    table = stmt.instance_variable_get(:@ast).relation
    execute stmt.to_sql
    projections = schema[table.name.to_sym].column_names.map{ |c| table[c.to_sym] }
    read(
      table.project(*projections).where(
        table.primary_key.eq(
          Arel.sql(last_insert_rowid(table.name, table.primary_key.name).to_s)
        )
      )
    )[0]
  end
end

#destroy(stmt) ⇒ Object 



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# File 'lib/arc/data_stores/abstract/store.rb', line 65

def destroy stmt
  case stmt
  when String
    execute stmt
  when Arel::DeleteManager
    execute stmt.to_sql
  end
end

#execute(query) ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/arc/data_stores/abstract/store.rb', line 78

def execute query
  #adapters should override this method to execute a query against the database
  #the methods should return an array-like object of hash-like objects
  raise NotImplementedError
end

#last_insert_rowid(table_name, pk_name) ⇒ Object 



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# File 'lib/arc/data_stores/abstract/store.rb', line 74

def last_insert_rowid table_name, pk_name
  'last_insert_rowid()'
end

#read(query) ⇒ Object 



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# File 'lib/arc/data_stores/abstract/store.rb', line 21

def read query
  case query
  when String
    execute(query).symbolize_keys!
  when Arel::SelectManager
    result_for query
  end
end

#result_for(query) ⇒ Object 



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# File 'lib/arc/data_stores/abstract/store.rb', line 109

def result_for query
  mappings = type_mappings_for query
  rows = read(query.to_sql)
  return Array.new(rows.size) do |index|
    Hash.new do |hash, key|
      hash[key] = cast rows[index][key], mappings[key]
    end
  end
end

#schema ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/arc/data_stores/abstract/store.rb', line 17

def schema
  raise NotImplementedError
end

#type_mappings_for(query) ⇒ Object 



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# File 'lib/arc/data_stores/abstract/store.rb', line 86

def type_mappings_for query
  type_mappings = {}
  query.instance_variable_get(:@ctx).projections.each do |projection|
    is_alias = projection.respond_to?(:right)
    relation = is_alias ? projection.left.relation : projection.relation

    root_projection = is_alias ? projection.left : projection
    relation_is_alias = root_projection.relation.respond_to?(:left)

    root_relation = relation_is_alias ? relation.left : relation

    table_name = root_relation.name
    result_column_name = is_alias ? projection.right.to_sym : projection.name
    table_column_name = root_projection.name

    table = Arel::Table.engine[table_name.to_sym]
    column = table[table_column_name.to_sym]

    type_mappings[result_column_name] = column.type.to_sym
  end
  type_mappings
end

#update(stmt, id = nil) ⇒ Object 



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# File 'lib/arc/data_stores/abstract/store.rb', line 48

def update stmt, id=nil
  case stmt
  when String
    execute stmt
  when Arel::UpdateManager
    execute stmt.to_sql
    if id
      table = stmt.instance_variable_get(:@ast).relation
      projections = schema[table.name.to_sym].column_names.map{ |c| table[c.to_sym] }
      read(
        table.project(*projections)
          .where(table.primary_key.eq id)
      )[0]
    end
  end
end