Class: PGresult

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
ext/pg.c,
ext/pg.c

Overview

******************************************************************

The class to represent the query result tuples (rows).
An instance of this class is created as the result of every query.
You may need to invoke the #clear method of the instance when finished with
the result for better memory performance.

Example:
   require 'pg'
   conn = PGconn.open(:dbname => 'test')
   res  = conn.exec('SELECT 1 AS a, 2 AS b, NULL AS c')
   res.getvalue(0,0) # '1'
   res[0]['b']       # '2'
   res[0]['c']       # nil

Constant Summary collapse

PGRES_EMPTY_QUERY =

The string sent to the server was empty.

#result_status constant
PGRES_COMMAND_OK =

Successful completion of a command returning no data.

#result_status constant
PGRES_TUPLES_OK =

Successful completion of a command returning data

(such as a SELECT or SHOW).

#result_status constant
PGRES_COPY_OUT =

Copy Out (from server) data transfer started.

#result_status constant
PGRES_COPY_IN =

Copy In (to server) data transfer started.

#result_status constant
PGRES_BAD_RESPONSE =

The server’s response was not understood.

#result_status constant
PGRES_NONFATAL_ERROR =

A nonfatal error (a notice or warning) occurred.

#result_status constant
PGRES_FATAL_ERROR =

A fatal error occurred.

#result_status constant
PG_DIAG_SEVERITY =

The severity; the field contents are ERROR, FATAL, or PANIC (in an error message), or WARNING, NOTICE, DEBUG, INFO, or LOG (in a notice message), or a localized translation of one of these. Always present.

#result_error_field argument constant
PG_DIAG_SQLSTATE =

The SQLSTATE code for the error. The SQLSTATE code identies the type of error that has occurred; it can be used by front-end applications to perform specic operations (such as er- ror handling) in response to a particular database error. For a list of the possible SQLSTATE codes, see Appendix A. This eld is not localizable, and is always present.

#result_error_field argument constant
PG_DIAG_MESSAGE_PRIMARY =

The primary human-readable error message (typically one line). Always present.

#result_error_field argument constant
PG_DIAG_MESSAGE_DETAIL =

Detail: an optional secondary error message carrying more detail about the problem. Might run to multiple lines.

#result_error_field argument constant
PG_DIAG_MESSAGE_HINT =

Hint: an optional suggestion what to do about the problem. This is intended to differ from detail in that it offers advice (potentially inappropriate) rather than hard facts. Might run to multiple lines.

#result_error_field argument constant
PG_DIAG_STATEMENT_POSITION =

A string containing a decimal integer indicating an error cursor position as an index into the original statement string. The rst character has index 1, and positions are measured in characters not bytes.

#result_error_field argument constant
PG_DIAG_INTERNAL_POSITION =

This is dened the same as the PG_DIAG_STATEMENT_POSITION eld, but it is used when the cursor position refers to an internally generated command rather than the one submitted by the client. The PG_DIAG_INTERNAL_QUERY eld will always appear when this eld appears.

#result_error_field argument constant
PG_DIAG_INTERNAL_QUERY =

The text of a failed internally-generated command. This could be, for example, a SQL query issued by a PL/pgSQL function.

#result_error_field argument constant
PG_DIAG_CONTEXT =

An indication of the context in which the error occurred. Presently this includes a call stack traceback of active procedural language functions and internally-generated queries. The trace is one entry per line, most recent rst.

#result_error_field argument constant
PG_DIAG_SOURCE_FILE =

The le name of the source-code location where the error was reported.

#result_error_field argument constant
PG_DIAG_SOURCE_LINE =

The line number of the source-code location where the error was reported.

#result_error_field argument constant
PG_DIAG_SOURCE_FUNCTION =

The name of the source-code function reporting the error.

#result_error_field argument constant
InvalidOid =

Invalid OID constant

INT2FIX(InvalidOid)

Instance Method Summary collapse

Instance Method Details

#[](n) ⇒ Hash

Returns tuple n as a hash.

Returns:

  • (Hash) 


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# File 'ext/pg.c', line 3478

static VALUE
pgresult_aref(VALUE self, VALUE index)
{
	PGresult *result = get_pgresult(self);
	int tuple_num = NUM2INT(index);
	int field_num;
	VALUE fname,val;
	VALUE tuple;

	if ( tuple_num < 0 || tuple_num >= PQntuples(result) )
		rb_raise( rb_eIndexError, "Index %d is out of range", tuple_num );

	tuple = rb_hash_new();
	for ( field_num = 0; field_num < PQnfields(result); field_num++ ) {
		fname = rb_tainted_str_new2( PQfname(result,field_num) );
		ASSOCIATE_INDEX(fname, self);
		if ( PQgetisnull(result, tuple_num, field_num) ) {
			rb_hash_aset( tuple, fname, Qnil );
		}
		else {
			val = rb_tainted_str_new( PQgetvalue(result, tuple_num, field_num ),
			                          PQgetlength(result, tuple_num, field_num) );

			/* associate client encoding for text format only */
			if ( 0 == PQfformat(result, field_num) ) {
				ASSOCIATE_INDEX( val, self );
			} else {
#ifdef M17N_SUPPORTED
				rb_enc_associate( val, rb_ascii8bit_encoding() );
#endif
			}
			rb_hash_aset( tuple, fname, val );
		}
	}
	return tuple;
}

#clear ⇒ nil

Clears the PGresult object as the result of the query.

Returns:

  • (nil) 


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# File 'ext/pg.c', line 3084

static VALUE
pgresult_clear(VALUE self)
{
	PQclear(get_pgresult(self));
	DATA_PTR(self) = NULL;
	return Qnil;
}

#cmd_status ⇒ String

Returns the status string of the last query command.

Returns:

  • (String) 


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# File 'ext/pg.c', line 3423

static VALUE
pgresult_cmd_status(VALUE self)
{
	VALUE ret = rb_tainted_str_new2(PQcmdStatus(get_pgresult(self)));
	ASSOCIATE_INDEX(ret, self);
	return ret;
}

#cmd_tuples ⇒ Fixnum Also known as: cmdtuples

Returns the number of tuples (rows) affected by the SQL command.

If the SQL command that generated the PGresult was not one of:

  • INSERT

  • UPDATE

  • DELETE

  • MOVE

  • FETCH

or if no tuples were affected, 0 is returned.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3445

static VALUE
pgresult_cmd_tuples(VALUE self)
{
	long n;
	n = strtol(PQcmdTuples(get_pgresult(self)),NULL, 10);
	return INT2NUM(n);
}

#column_values(n) ⇒ Array

Returns an Array of the values from the nth column of each tuple in the result.

Returns:

  • (Array) 


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# File 'ext/pg.c', line 3573

static VALUE
pgresult_column_values(VALUE self, VALUE index)
{
	int col = NUM2INT( index );
	return make_column_result_array( self, col );
}

#each {|tuple| ... } ⇒ Object

Invokes block for each tuple in the result set.

Yields:

  • (tuple) 


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# File 'ext/pg.c', line 3643

static VALUE
pgresult_each(VALUE self)
{
	PGresult *result = get_pgresult(self);
	int tuple_num;

	for(tuple_num = 0; tuple_num < PQntuples(result); tuple_num++) {
		rb_yield(pgresult_aref(self, INT2NUM(tuple_num)));
	}
	return self;
}

#fformat(column_number) ⇒ Fixnum

Returns the format (0 for text, 1 for binary) of column column_number.

Raises ArgumentError if column_number is out of range.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3219

static VALUE
pgresult_fformat(VALUE self, VALUE column_number)
{
	PGresult *result = get_pgresult(self);
	int fnumber = NUM2INT(column_number);
	if (fnumber < 0 || fnumber >= PQnfields(result)) {
		rb_raise(rb_eArgError, "Column number is out of range: %d", 
			fnumber);
	}
	return INT2FIX(PQfformat(result, fnumber));
}

#field_values(field) ⇒ Array

Returns an Array of the values from the given field of each tuple in the result.

Returns:

  • (Array) 


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# File 'ext/pg.c', line 3588

static VALUE
pgresult_field_values( VALUE self, VALUE field )
{
	PGresult *result = get_pgresult( self );
	const char *fieldname = RSTRING_PTR( field );
	int fnum = PQfnumber( result, fieldname );

	if ( fnum < 0 )
		rb_raise( rb_eIndexError, "no such field '%s' in result", fieldname );

	return make_column_result_array( self, fnum );
}

#fields ⇒ Array

Returns an array of Strings representing the names of the fields in the result.

Returns:

  • (Array) 


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# File 'ext/pg.c', line 3661

static VALUE
pgresult_fields(VALUE self)
{
	PGresult *result;
	VALUE ary;
	int n, i;

	result = get_pgresult(self);
	n = PQnfields(result);
	ary = rb_ary_new2(n);
	for (i=0;i<n;i++) {
		VALUE val = rb_tainted_str_new2(PQfname(result, i));
		ASSOCIATE_INDEX(val, self);
		rb_ary_push(ary, val);
	}
	return ary;
}

#fmod(column_number) ⇒ Object

Returns the type modifier associated with column column_number. See the #ftype method for an example of how to use this.

Raises an ArgumentError if column_number is out of range.



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# File 'ext/pg.c', line 3269

static VALUE
pgresult_fmod(VALUE self, VALUE column_number)
{
	PGresult *result = get_pgresult(self);
	int fnumber = NUM2INT(column_number);
	int modifier;
	if (fnumber < 0 || fnumber >= PQnfields(result)) {
		rb_raise(rb_eArgError, "Column number is out of range: %d", 
			fnumber);
	}
	modifier = PQfmod(result,fnumber);

	return INT2NUM(modifier);
}

#fname(index) ⇒ String

Returns the name of the column corresponding to index.

Returns:

  • (String) 


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# File 'ext/pg.c', line 3122

static VALUE
pgresult_fname(VALUE self, VALUE index)
{
	VALUE fname;
	PGresult *result;
	int i = NUM2INT(index);

	result = get_pgresult(self);
	if (i < 0 || i >= PQnfields(result)) {
		rb_raise(rb_eArgError,"invalid field number %d", i);
	}
	fname = rb_tainted_str_new2(PQfname(result, i));
	ASSOCIATE_INDEX(fname, self);
	return fname;
}

#fnumber(name) ⇒ Fixnum

Returns the index of the field specified by the string name.

Raises an ArgumentError if the specified name isn’t one of the field names; raises a TypeError if name is not a String.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3147

static VALUE
pgresult_fnumber(VALUE self, VALUE name)
{
	int n;

	Check_Type(name, T_STRING);

	n = PQfnumber(get_pgresult(self), StringValuePtr(name));
	if (n == -1) {
		rb_raise(rb_eArgError,"Unknown field: %s", StringValuePtr(name));
	}
	return INT2FIX(n);
}

#fsize(index) ⇒ Object

Returns the size of the field type in bytes. Returns -1 if the field is variable sized.

res = conn.exec("SELECT myInt, myVarChar50 FROM foo")
res.size(0) => 4
res.size(1) => -1



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# File 'ext/pg.c', line 3294

static VALUE
pgresult_fsize(VALUE self, VALUE index)
{
	PGresult *result;
	int i = NUM2INT(index);

	result = get_pgresult(self);
	if (i < 0 || i >= PQnfields(result)) {
		rb_raise(rb_eArgError,"invalid field number %d", i);
	}
	return INT2NUM(PQfsize(result, i));
}

#ftable(column_number) ⇒ Fixnum

Returns the Oid of the table from which the column column_number was fetched.

Raises ArgumentError if column_number is out of range or if the Oid is undefined for that column.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3171

static VALUE
pgresult_ftable(VALUE self, VALUE column_number)
{
	Oid n ;
	int col_number = NUM2INT(column_number);
	PGresult *pgresult = get_pgresult(self);

	if( col_number < 0 || col_number >= PQnfields(pgresult)) 
		rb_raise(rb_eArgError,"Invalid column index: %d", col_number);

	n = PQftable(pgresult, col_number);
	return INT2FIX(n);
}

#ftablecol(column_number) ⇒ Fixnum

Returns the column number (within its table) of the table from which the column column_number is made up.

Raises ArgumentError if column_number is out of range or if the column number from its table is undefined for that column.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3195

static VALUE
pgresult_ftablecol(VALUE self, VALUE column_number)
{
	int col_number = NUM2INT(column_number);
	PGresult *pgresult = get_pgresult(self);

	int n;

	if( col_number < 0 || col_number >= PQnfields(pgresult)) 
		rb_raise(rb_eArgError,"Invalid column index: %d", col_number);

	n = PQftablecol(pgresult, col_number);
	return INT2FIX(n);
}

#ftype(column_number) ⇒ Object

Returns the data type associated with column_number.

The integer returned is the internal OID number (in PostgreSQL) of the type. To get a human-readable value for the type, use the returned OID and the field’s #fmod value with the format_type() SQL function:

# Get the type of the second column of the result 'res'
typename = conn.
  exec( "SELECT format_type($1,$2)", [res.ftype(1), res.fmod(1)] ).
  getvalue( 0, 0 )

Raises an ArgumentError if column_number is out of range.



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# File 'ext/pg.c', line 3249

static VALUE
pgresult_ftype(VALUE self, VALUE index)
{
	PGresult* result = get_pgresult(self);
	int i = NUM2INT(index);
	if (i < 0 || i >= PQnfields(result)) {
		rb_raise(rb_eArgError, "invalid field number %d", i);
	}
	return INT2NUM(PQftype(result, i));
}

#getisnull(tuple_position, field_position) ⇒ Boolean

Returns true if the specified value is nil; false otherwise.

Returns:

  • (Boolean) 


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# File 'ext/pg.c', line 3343

static VALUE
pgresult_getisnull(VALUE self, VALUE tup_num, VALUE field_num)
{
	PGresult *result;
	int i = NUM2INT(tup_num);
	int j = NUM2INT(field_num);

	result = get_pgresult(self);
	if (i < 0 || i >= PQntuples(result)) {
		rb_raise(rb_eArgError,"invalid tuple number %d", i);
	}
	if (j < 0 || j >= PQnfields(result)) {
		rb_raise(rb_eArgError,"invalid field number %d", j);
	}
	return PQgetisnull(result, i, j) ? Qtrue : Qfalse;
}

#getlength(tup_num, field_num) ⇒ Fixnum

Returns the (String) length of the field in bytes.

Equivalent to res.value(tup_num,field_num).length.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3368

static VALUE
pgresult_getlength(VALUE self, VALUE tup_num, VALUE field_num)
{
	PGresult *result;
	int i = NUM2INT(tup_num);
	int j = NUM2INT(field_num);

	result = get_pgresult(self);
	if (i < 0 || i >= PQntuples(result)) {
		rb_raise(rb_eArgError,"invalid tuple number %d", i);
	}
	if (j < 0 || j >= PQnfields(result)) {
		rb_raise(rb_eArgError,"invalid field number %d", j);
	}
	return INT2FIX(PQgetlength(result, i, j));
}

#getvalue(tup_num, field_num) ⇒ Object

Returns the value in tuple number tup_num, field field_num, or nil if the field is NULL.



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# File 'ext/pg.c', line 3314

static VALUE
pgresult_getvalue(VALUE self, VALUE tup_num, VALUE field_num)
{
	VALUE ret;
	PGresult *result;
	int i = NUM2INT(tup_num);
	int j = NUM2INT(field_num);

	result = get_pgresult(self);
	if(i < 0 || i >= PQntuples(result)) {
		rb_raise(rb_eArgError,"invalid tuple number %d", i);
	}
	if(j < 0 || j >= PQnfields(result)) {
		rb_raise(rb_eArgError,"invalid field number %d", j);
	}
	if(PQgetisnull(result, i, j))
		return Qnil;
	ret = rb_tainted_str_new(PQgetvalue(result, i, j), 
				PQgetlength(result, i, j));
	ASSOCIATE_INDEX(ret, self);
	return ret;
}

#nfields ⇒ Fixnum Also known as: num_fields

Returns the number of columns in the query result.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3110

static VALUE
pgresult_nfields(VALUE self)
{
	return INT2NUM(PQnfields(get_pgresult(self)));
}

#nparams ⇒ Fixnum

Returns the number of parameters of a prepared statement. Only useful for the result returned by conn.describePrepared

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3392

static VALUE
pgresult_nparams(VALUE self)
{
	PGresult *result;

	result = get_pgresult(self);
	return INT2FIX(PQnparams(result));
}

#ntuples ⇒ Fixnum Also known as: num_tuples

Returns the number of tuples in the query result.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3098

static VALUE
pgresult_ntuples(VALUE self)
{
	return INT2FIX(PQntuples(get_pgresult(self)));
}

#oid_value ⇒ Fixnum

Returns the oid of the inserted row if applicable, otherwise nil.

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3460

static VALUE
pgresult_oid_value(VALUE self)
{
	Oid n = PQoidValue(get_pgresult(self));
	if (n == InvalidOid)
		return Qnil;
	else
		return INT2FIX(n);
}

#paramtype(param_number) ⇒ Oid

Returns the Oid of the data type of parameter param_number. Only useful for the result returned by conn.describePrepared

Returns:

  • (Oid) 


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# File 'ext/pg.c', line 3408

static VALUE
pgresult_paramtype(VALUE self, VALUE param_number)
{
	PGresult *result;

	result = get_pgresult(self);
	return INT2FIX(PQparamtype(result,NUM2INT(param_number)));
}

#res_status(status) ⇒ String

Returns the string representation of status status.

Returns:

  • (String) 


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# File 'ext/pg.c', line 3026

static VALUE
pgresult_res_status(VALUE self, VALUE status)
{
	VALUE ret = rb_tainted_str_new2(PQresStatus(NUM2INT(status)));
	ASSOCIATE_INDEX(ret, self);
	return ret;
}

#result_error_field(fieldcode) ⇒ String

Returns the individual field of an error.

fieldcode is one of:

  • PG_DIAG_SEVERITY

  • PG_DIAG_SQLSTATE

  • PG_DIAG_MESSAGE_PRIMARY

  • PG_DIAG_MESSAGE_DETAIL

  • PG_DIAG_MESSAGE_HINT

  • PG_DIAG_STATEMENT_POSITION

  • PG_DIAG_INTERNAL_POSITION

  • PG_DIAG_INTERNAL_QUERY

  • PG_DIAG_CONTEXT

  • PG_DIAG_SOURCE_FILE

  • PG_DIAG_SOURCE_LINE

  • PG_DIAG_SOURCE_FUNCTION

Returns:

  • (String) 


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# File 'ext/pg.c', line 3068

static VALUE
pgresult_result_error_field(VALUE self, VALUE field)
{
	PGresult *result = get_pgresult(self);
	int fieldcode = NUM2INT(field);
	VALUE ret = rb_tainted_str_new2(PQresultErrorField(result,fieldcode));
	ASSOCIATE_INDEX(ret, self);
	return ret;
}

#result_error_message ⇒ String

Returns the error message of the command as a string.

Returns:

  • (String) 


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# File 'ext/pg.c', line 3040

static VALUE
pgresult_result_error_message(VALUE self)
{
	VALUE ret = rb_tainted_str_new2(PQresultErrorMessage(get_pgresult(self)));
	ASSOCIATE_INDEX(ret, self);
	return ret;
}

#result_status ⇒ Fixnum

Returns the status of the query. The status value is one of:

  • PGRES_EMPTY_QUERY

  • PGRES_COMMAND_OK

  • PGRES_TUPLES_OK

  • PGRES_COPY_OUT

  • PGRES_COPY_IN

  • PGRES_BAD_RESPONSE

  • PGRES_NONFATAL_ERROR

  • PGRES_FATAL_ERROR

Returns:

  • (Fixnum) 


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# File 'ext/pg.c', line 3013

static VALUE
pgresult_result_status(VALUE self)
{
	return INT2FIX(PQresultStatus(get_pgresult(self)));
}

#values ⇒ Array

Returns all tuples as an array of arrays.

Returns:

  • (Array) 


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# File 'ext/pg.c', line 3522

static VALUE
pgresult_values(VALUE self, VALUE index)
{
	PGresult* result = (PGresult*) get_pgresult(self);
	int row;
	int field;
	int num_rows = PQntuples(result);
	int num_fields = PQnfields(result);
	VALUE ary = rb_ary_new2(num_rows);

	for ( row = 0; row < num_rows; row++ ) {
		/* create new row */
		VALUE new_row = rb_ary_new2(num_fields);

		/* add to return array */
		rb_ary_store( ary, row, new_row );

		/* populate it */
		for ( field = 0; field < num_fields; field++ ) {
			if ( PQgetisnull(result, row, field) ) {
				rb_ary_store( new_row, field, Qnil );
			}
			else {
				VALUE val = rb_tainted_str_new( PQgetvalue(result, row, field), 
				                                PQgetlength(result, row, field) );

				/* associate client encoding for text format only */
				if ( 0 == PQfformat(result, field) ) {
					ASSOCIATE_INDEX( val, self );
				} else {
#ifdef M17N_SUPPORTED
					rb_enc_associate( val, rb_ascii8bit_encoding() );
#endif
				}

				rb_ary_store( new_row, field, val );
			}
		}
	}
	return ary;
}