Class: Json2sql::WhereRelation

Inherits:
Object
  • Object
show all
Defined in:
lib/json2sql/where_relation.rb

Constant Summary collapse

NONE = 
:none
CHILD = 
:child
PARENT = 
:parent

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(table, kind) ⇒ WhereRelation

Returns a new instance of WhereRelation.



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# File 'lib/json2sql/where_relation.rb', line 11

def initialize(table, kind)

  @table = table.to_s

  @kind  = kind
end

Instance Attribute Details

#kind ⇒ Object (readonly)

Returns the value of attribute kind.



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# File 'lib/json2sql/where_relation.rb', line 9

def kind
  @kind
end

#table ⇒ Object (readonly)

Returns the value of attribute table.



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# File 'lib/json2sql/where_relation.rb', line 9

def table
  @table
end

Class Method Details

.child(table) ⇒ Object

Factory: foreign key is on the child table pointing to the parent. Produces: ‘parent`.`child_id` = `current`.`id`



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# File 'lib/json2sql/where_relation.rb', line 28

def self.child(table)

  new(table, CHILD)
end

.none(table) ⇒ Object

Factory: no relationship (top-level query).



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# File 'lib/json2sql/where_relation.rb', line 20

def self.none(table)

  new(table, NONE)
end

.parent(table) ⇒ Object

Factory: foreign key is on the current/parent table pointing to the child. Produces: ‘current`.`parent_id` = `parent`.`id`



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# File 'lib/json2sql/where_relation.rb', line 36

def self.parent(table)

  new(table, PARENT)
end

Instance Method Details

#build_table_id(tbl) ⇒ Object

Converts a (possibly plural) table name to its foreign-key column name wrapped in backticks.

"users"      → "`user_id`"
"categories" → "`category_id`"
"admins"     → "`admin_id`"



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# File 'lib/json2sql/where_relation.rb', line 87

def build_table_id(tbl)

  base = Sanitizer.keyword(tbl.to_s)

  return "`#{base[0..-4]}y_id`" if base.end_with?("ies")

  return "`#{base[0..-2]}_id`" if base.end_with?("s")

  "`#{base}_id`"
end

#build_table_relation(sql, current) ⇒ Object

Appends the JOIN condition for this relationship into sql. current is the name of the table being queried.



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# File 'lib/json2sql/where_relation.rb', line 44

def build_table_relation(sql, current)

  current = current.to_s

  if kind == CHILD

    sql << Sanitizer.keyword_wrap(table)

    sql << "."

    sql << build_table_id(current)

    sql << " = "

    sql << Sanitizer.keyword_wrap(current)

    sql << ".`id`"

    return
  end

  if kind == PARENT

    sql << Sanitizer.keyword_wrap(current)

    sql << "."

    sql << build_table_id(table)

    sql << " = "

    sql << Sanitizer.keyword_wrap(table)

    sql << ".`id`"
  end
end