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) 


3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
 
# File 'ext/pg.c', line 3511

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)) {
				fflush( stdout );
				ASSOCIATE_INDEX(val, self);
			} else {
#ifdef M17N_SUPPORTED
				fflush( stdout );
				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) 


3117
3118
3119
3120
3121
3122
3123
 
# File 'ext/pg.c', line 3117

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) 


3456
3457
3458
3459
3460
3461
3462
 
# File 'ext/pg.c', line 3456

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) 


3478
3479
3480
3481
3482
3483
3484
 
# File 'ext/pg.c', line 3478

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) 


3558
3559
3560
3561
3562
3563
 
# File 'ext/pg.c', line 3558

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) 


3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
 
# File 'ext/pg.c', line 3628

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) 


3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
 
# File 'ext/pg.c', line 3252

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) 


3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
 
# File 'ext/pg.c', line 3573

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) 


3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
 
# File 'ext/pg.c', line 3646

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.



3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
 
# File 'ext/pg.c', line 3302

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) 


3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
 
# File 'ext/pg.c', line 3155

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) 


3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
 
# File 'ext/pg.c', line 3180

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



3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
 
# File 'ext/pg.c', line 3327

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) 


3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
 
# File 'ext/pg.c', line 3204

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) 


3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
 
# File 'ext/pg.c', line 3228

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.



3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
 
# File 'ext/pg.c', line 3282

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) 


3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
 
# File 'ext/pg.c', line 3376

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) 


3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
 
# File 'ext/pg.c', line 3401

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.



3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
 
# File 'ext/pg.c', line 3347

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) 


3143
3144
3145
3146
3147
 
# File 'ext/pg.c', line 3143

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) 


3425
3426
3427
3428
3429
3430
3431
3432
 
# File 'ext/pg.c', line 3425

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) 


3131
3132
3133
3134
3135
 
# File 'ext/pg.c', line 3131

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) 


3493
3494
3495
3496
3497
3498
3499
3500
3501
 
# File 'ext/pg.c', line 3493

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) 


3441
3442
3443
3444
3445
3446
3447
3448
 
# File 'ext/pg.c', line 3441

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) 


3059
3060
3061
3062
3063
3064
3065
 
# File 'ext/pg.c', line 3059

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) 


3101
3102
3103
3104
3105
3106
3107
3108
3109
 
# File 'ext/pg.c', line 3101

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) 


3073
3074
3075
3076
3077
3078
3079
 
# File 'ext/pg.c', line 3073

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) 


3046
3047
3048
3049
3050
 
# File 'ext/pg.c', line 3046

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