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Class: PG::TypeMapByColumn

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain:
self, TypeMap
Instance Chain:
self, TypeMap::DefaultTypeMappable, TypeMap
Inherits: PG::TypeMap
Defined in: ext/pg_type_map_by_column.c,
ext/pg_type_map_by_column.c,
lib/pg/type_map_by_column.rb

Overview

This type map casts values by a coder assigned per field/column.

Each TypeMapByColumn has a fixed list of either encoders or decoders, that is defined at .new . A type map with encoders is usable for type casting query bind parameters and COPY data for Connection#put_copy_data . A type map with decoders is usable for type casting of result values and COPY data from Connection#get_copy_data .

TypeMapByColumn objects are in particular useful in conjunction with prepared statements, since they can be cached alongside with the statement handle.

This type map strategy is also used internally by TypeMapByOid, when the number of rows of a result set exceeds a given limit.

Class Method Summary

  • .new(coders) constructor

    Builds a new type map and assigns a list of coders for the given column.

Instance Attribute Summary

TypeMap::DefaultTypeMappable - Included

#default_type_map

Returns the default TypeMap that is currently set for values that could not be casted by this type map.
#default_type_map=

Set the default TypeMap that is used for values that could not be casted by this type map.

Instance Method Summary

TypeMap::DefaultTypeMappable - Included

#with_default_type_map

Set the default TypeMap that is used for values that could not be casted by this type map.

Constructor Details

.new(coders)

Builds a new type map and assigns a list of coders for the given column. #coders must be an Array of Coder objects or nil values. The length of the Array corresponds to the number of columns or bind parameters this type map is usable for.

A nil value will forward the given field to the #default_type_map .

[ GitHub ] 

  


# File 'ext/pg_type_map_by_column.c', line 262



static VALUE
pg_tmbc_init(VALUE self, VALUE conv_ary)
{
	long i;
	t_tmbc *this;
	int conv_ary_len;

	rb_check_frozen(self);
	Check_Type(conv_ary, T_ARRAY);
	conv_ary_len = RARRAY_LENINT(conv_ary);
	this = xmalloc(sizeof(t_tmbc) + sizeof(struct pg_tmbc_converter) * conv_ary_len);
	/* Set nfields to 0 at first, so that GC mark function doesn't access uninitialized memory. */
	this->nfields = 0;
	this->typemap.funcs = pg_tmbc_funcs;
	RB_OBJ_WRITE(self, &this->typemap.default_typemap, pg_typemap_all_strings);
	RTYPEDDATA_DATA(self) = this;

	for(i=0; i<conv_ary_len; i++)
	{
		VALUE obj = rb_ary_entry(conv_ary, i);

		if( obj == Qnil ){
			/* no type cast */
			this->convs[i].cconv = NULL;
		} else {
			t_pg_coder *p_coder;
			/* Check argument type and store the coder pointer */
			TypedData_Get_Struct(obj, t_pg_coder, &pg_coder_type, p_coder);
			RB_OBJ_WRITTEN(self, Qnil, p_coder->coder_obj);
			this->convs[i].cconv = p_coder;
		}
	}

	this->nfields = conv_ary_len;

	return self;
}


  







Instance Method Details



  

    #coders  ⇒ Array   



  

    

Array of Coder objects. The length of the Array corresponds to the number of columns or bind parameters this type map is usable for.


  



  [ GitHub ]


  

  


# File 'ext/pg_type_map_by_column.c', line 307



static VALUE
pg_tmbc_coders(VALUE self)
{
	int i;
	t_tmbc *this = RTYPEDDATA_DATA( self );
	VALUE ary_coders = rb_ary_new();

	for( i=0; i<this->nfields; i++){
		t_pg_coder *conv = this->convs[i].cconv;
		if( conv ) {
			rb_ary_push( ary_coders, conv->coder_obj );
		} else {
			rb_ary_push( ary_coders, Qnil );
		}
	}

	return rb_obj_freeze(ary_coders);
}


  








  

    #inspect  
  

  [ GitHub ]


  

  


# File 'lib/pg/type_map_by_column.rb', line 12



def inspect
	type_strings = coders.map{|c| c ? c.inspect_short : 'nil' }
	"#<#{self.class} #{type_strings.join(' ')}>"
end


  








  

    #oids  
  



  

    

Returns the type oids of the assigned coders.


  



  [ GitHub ]


  

  


# File 'lib/pg/type_map_by_column.rb', line 8



def oids
	coders.map{|c| c.oid if c }
end