Class: Flounder::Query::Base

Inherits:
Object
  • Object
show all
Includes:
Helpers::Entity
Defined in:
lib/flounder/query/base.rb

Direct Known Subclasses

Delete, Insert, Select, Update

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Helpers::Entity

#convert_to_entity, #entity_like?

Constructor Details

#initialize(domain, manager_klass, entity) ⇒ Base

Returns a new instance of Base.



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# File 'lib/flounder/query/base.rb', line 10

def initialize domain, manager_klass, entity
  @domain = domain
  @engine = Flounder::Engine.new(domain.connection_pool)
  @manager = manager_klass.new(engine)
  @entity = entity

  @bind_values = []
end

Instance Attribute Details

#bind_values ⇒ Object (readonly)

Bound values in this query.



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# File 'lib/flounder/query/base.rb', line 24

def bind_values
  @bind_values
end

#domain ⇒ Object (readonly)

Domain that this query was issued from.



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# File 'lib/flounder/query/base.rb', line 20

def domain
  @domain
end

#engine ⇒ Object (readonly)

Database engine that links Arel to Postgres.



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# File 'lib/flounder/query/base.rb', line 22

def engine
  @engine
end

#entity ⇒ Object (readonly)

Entity this query operates on.



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# File 'lib/flounder/query/base.rb', line 28

def entity
  @entity
end

#manager ⇒ Object (readonly)

Arel *Manager that accumulates this query.



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# File 'lib/flounder/query/base.rb', line 26

def manager
  @manager
end

Instance Method Details

#column_name_to_entity(name) ⇒ Object

Implement this if your column names in the query allow inferring the entity and the column name. Return them as a tuple <entity, name>.



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# File 'lib/flounder/query/base.rb', line 81

def column_name_to_entity name
end

#kick(connection = nil) ⇒ Object

Returns all rows of the query result as an array. Individual rows are mapped to objects using the row mapper.



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# File 'lib/flounder/query/base.rb', line 59

def kick connection=nil
  all = nil
  connection ||= engine

  measure do
    result = connection.exec(self.to_sql, bind_values) 

    descriptor = ::Flounder::Result::Descriptor.new(
      connection, entity, result, &method(:column_name_to_entity))

    all = Array.new(result.ntuples, nil)
    result.ntuples.times do |row_idx|
      all[row_idx] = descriptor.row(row_idx)
    end
  end

  all
end

#measure ⇒ Object

Measures the block given to it and logs time spent in the block to the domain.



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# File 'lib/flounder/query/base.rb', line 87

def measure
  measure = Benchmark.measure {
    yield        
  }
  domain.log_bm measure
end

#parse_conditions(*conditions, &apply) ⇒ Object

Parses a conditions array like it is found with #where and #having and calls the block for each condition bit. Returns self.

Example:

parse_conditions(conditions) { |bit| manager.where(bit) }



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# File 'lib/flounder/query/base.rb', line 100

def parse_conditions *conditions, &apply
  conditions = conditions.dup

  resolve_entity = entity

  # is the first argument an entity? if yes, interpret field names relative
  # to that entity. 
  if conditions.size > 1 && entity_like?(conditions.first)
    resolve_entity = convert_to_entity(conditions.shift)
  end

  # is this a hash? extract the first element
  if conditions.size == 1 && conditions.first.kind_of?(Hash)
    conditions = conditions.first 

    conditions.each do |k, v|
      apply.call(
        transform_tuple(resolve_entity, k, v))
    end
    return self
  end

  # or maybe this is a Flounder::Expression::Expr? 
  if conditions.size == 1 && conditions.first.kind_of?(Flounder::Expression::Expr)
    condition = conditions.first
    apply.call(
      Arel::Nodes::SqlLiteral.new(condition.to_sql))
    
    return self
  end

  # maybe conditions is of the second form?
  conditions.each do |cond_str, *values|
    apply.call(
      Arel::Nodes::SqlLiteral.new(
        rewrite_bind_variables(cond_str, bind_values.size, values.size)))
    bind_values.concat values
  end
  return self
end

#to_sql ⇒ Object

Kickers



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# File 'lib/flounder/query/base.rb', line 49

def to_sql
  prepare_kick
  
  manager.to_sql.tap { |sql| 
    domain.log_sql(sql) }
end

#where(*conditions) ⇒ Object

Restricts the result returned to only those records that match the conditions.

Example: 

query.where(id: 1)            # ... WHERE id = 1 ...
query.where(:id => :user_id)  # ... WHERE id = user_id
query.where(:id.noteq => 1)   # ... WHERE id != 1



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# File 'lib/flounder/query/base.rb', line 39

def where *conditions
  parse_conditions(*conditions) { |bit| manager.where(bit) }
end

#with(name, query) ⇒ Object 



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# File 'lib/flounder/query/base.rb', line 43

def with name, query
  # Nodes::TableAlias.new(relation, name)
  manager.with(query.manager)
end