Class: Simple::SQL::Connection::Reflection

Inherits:
Object
  • Object
show all
Defined in:
lib/simple/sql/connection/reflection.rb

Constant Summary collapse

TIMESTAMP_COLUMN_NAMES = 
%w(inserted_at created_at updated_at)

Instance Method Summary collapse

Constructor Details

#initialize(connection) ⇒ Reflection

Returns a new instance of Reflection.



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# File 'lib/simple/sql/connection/reflection.rb', line 11

def initialize(connection)
  @connection = connection
end

Instance Method Details

#column_info(table_name) ⇒ Object 



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# File 'lib/simple/sql/connection/reflection.rb', line 45

def column_info(table_name)
  @column_info ||= {}
  @column_info[table_name] ||= _column_info(table_name)
end

#column_types(table_name) ⇒ Object

returns a Hash of column_name => column_type. Names are available both as Symbol and as String.



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# File 'lib/simple/sql/connection/reflection.rb', line 52

def column_types(table_name)
  @column_types ||= {}
  @column_types[table_name] ||= _column_types(table_name)
end

#columns(table_name) ⇒ Object 



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# File 'lib/simple/sql/connection/reflection.rb', line 41

def columns(table_name)
  column_info(table_name).keys
end

#looked_up_pg_classes ⇒ Object 



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# File 'lib/simple/sql/connection/reflection.rb', line 106

def looked_up_pg_classes
  @looked_up_pg_classes ||= Hash.new { |hsh, key| hsh[key] = _lookup_pg_class(key) }
end

#lookup_pg_class(oid) ⇒ Object 



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# File 'lib/simple/sql/connection/reflection.rb', line 110

def lookup_pg_class(oid)
  looked_up_pg_classes[oid]
end

#primary_key_columns(table_name) ⇒ Object 



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# File 'lib/simple/sql/connection/reflection.rb', line 19

def primary_key_columns(table_name)
  @connection.all <<~SQL, table_name
    SELECT pg_attribute.attname
    FROM   pg_index
    JOIN   pg_attribute ON pg_attribute.attrelid = pg_index.indrelid AND pg_attribute.attnum = ANY(pg_index.indkey)
    WHERE  pg_index.indrelid = $1::regclass
    AND    pg_index.indisprimary;
  SQL
end

#table_info(schema: "public") ⇒ Object 



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# File 'lib/simple/sql/connection/reflection.rb', line 57

def table_info(schema: "public")
  recs = @connection.all <<~SQL, schema, into: Hash
    SELECT table_schema || '.' || table_name AS name, *
    FROM information_schema.tables
    WHERE table_schema=$1
  SQL
  records_by_attr(recs, :name)
end

#tables(schema: "public") ⇒ Object 



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# File 'lib/simple/sql/connection/reflection.rb', line 15

def tables(schema: "public")
  table_info(schema: schema).keys
end

#timestamp_columns(table_name) ⇒ Object

timestamp_columns are columns that will be set automatically after inserting or updating a record. This includes:

  • inserted_at (for Ecto)

  • created_at (for ActiveRecord)

  • updated_at (for Ecto and ActiveRecord)



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# File 'lib/simple/sql/connection/reflection.rb', line 37

def timestamp_columns(table_name)
  columns(table_name) & TIMESTAMP_COLUMN_NAMES
end