Class: PG::Result

Inherits:
Object
  • Object
show all
Includes:
Enumerable, Constants
Defined in:
ext/pg_result.c,
lib/pg/result.rb,
ext/pg_result.c

Overview

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

The class to represent the query result tuples (rows).
An instance of this class is created as the result of every query.
All result rows and columns are stored in a memory block attached to the PG::Result object.
Whenever a value is accessed it is casted to a Ruby object by the assigned #type_map .

Since pg-1.1 the amount of memory in use by a PG::Result object is estimated and passed to ruby's garbage collector.
You can invoke the #clear method to force deallocation of memory of the instance when finished with the result for better memory performance.

Example:
   require 'pg'
   conn = PG.connect(: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

Constants included from Constants

Constants::CONNECTION_AUTH_OK, Constants::CONNECTION_AWAITING_RESPONSE, Constants::CONNECTION_BAD, Constants::CONNECTION_MADE, Constants::CONNECTION_NEEDED, Constants::CONNECTION_OK, Constants::CONNECTION_SETENV, Constants::CONNECTION_SSL_STARTUP, Constants::CONNECTION_STARTED, Constants::INVALID_OID, Constants::INV_READ, Constants::INV_WRITE, Constants::InvalidOid, Constants::PGRES_BAD_RESPONSE, Constants::PGRES_COMMAND_OK, Constants::PGRES_COPY_BOTH, Constants::PGRES_COPY_IN, Constants::PGRES_COPY_OUT, Constants::PGRES_EMPTY_QUERY, Constants::PGRES_FATAL_ERROR, Constants::PGRES_NONFATAL_ERROR, Constants::PGRES_POLLING_FAILED, Constants::PGRES_POLLING_OK, Constants::PGRES_POLLING_READING, Constants::PGRES_POLLING_WRITING, Constants::PGRES_SINGLE_TUPLE, Constants::PGRES_TUPLES_OK, Constants::PG_DIAG_COLUMN_NAME, Constants::PG_DIAG_CONSTRAINT_NAME, Constants::PG_DIAG_CONTEXT, Constants::PG_DIAG_DATATYPE_NAME, Constants::PG_DIAG_INTERNAL_POSITION, Constants::PG_DIAG_INTERNAL_QUERY, Constants::PG_DIAG_MESSAGE_DETAIL, Constants::PG_DIAG_MESSAGE_HINT, Constants::PG_DIAG_MESSAGE_PRIMARY, Constants::PG_DIAG_SCHEMA_NAME, Constants::PG_DIAG_SEVERITY, Constants::PG_DIAG_SOURCE_FILE, Constants::PG_DIAG_SOURCE_FUNCTION, Constants::PG_DIAG_SOURCE_LINE, Constants::PG_DIAG_SQLSTATE, Constants::PG_DIAG_STATEMENT_POSITION, Constants::PG_DIAG_TABLE_NAME, Constants::PQERRORS_DEFAULT, Constants::PQERRORS_TERSE, Constants::PQERRORS_VERBOSE, Constants::PQPING_NO_ATTEMPT, Constants::PQPING_NO_RESPONSE, Constants::PQPING_OK, Constants::PQPING_REJECT, Constants::PQTRANS_ACTIVE, Constants::PQTRANS_IDLE, Constants::PQTRANS_INERROR, Constants::PQTRANS_INTRANS, Constants::PQTRANS_UNKNOWN, Constants::SEEK_CUR, Constants::SEEK_END, Constants::SEEK_SET

Instance Method Summary collapse

Instance Method Details

#[](n) ⇒ Hash

Returns tuple n as a hash.

Returns:

  • (Hash)

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# File 'ext/pg_result.c', line 960

static VALUE
pgresult_aref(VALUE self, VALUE index)
{
	t_pg_result *this = pgresult_get_this_safe(self);
	int tuple_num = NUM2INT(index);
	int field_num;
	int num_tuples = PQntuples(this->pgresult);
	VALUE tuple;

	if( this->nfields == -1 )
		pgresult_init_fnames( self );

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

	/* We reuse the Hash of the previous output for larger row counts.
	 * This is somewhat faster than populating an empty Hash object. */
	tuple = NIL_P(this->tuple_hash) ? rb_hash_new() : this->tuple_hash;
	for ( field_num = 0; field_num < this->nfields; field_num++ ) {
		VALUE val = this->p_typemap->funcs.typecast_result_value(this->p_typemap, self, tuple_num, field_num);
		rb_hash_aset( tuple, this->fnames[field_num], val );
	}
	/* Store a copy of the filled hash for use at the next row. */
	if( num_tuples > 10 )
		this->tuple_hash = rb_hash_dup(tuple);

	return tuple;
}

#autoclear?Boolean

Returns true if the underlying C struct will be cleared automatically by libpq. Elsewise the result is cleared by PG::Result#clear or by the GC when it's no longer in use.

Returns:

  • (Boolean)

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# File 'ext/pg_result.c', line 297

VALUE
pgresult_autoclear_p( VALUE self )
{
	t_pg_result *this = pgresult_get_this(self);
	return this->autoclear ? Qtrue : Qfalse;
}

#checknil Also known as: check_result

Raises appropriate exception if PG::Result is in a bad state.

Returns:

  • (nil)

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# File 'ext/pg_result.c', line 198

VALUE
pg_result_check( VALUE self )
{
	t_pg_result *this = pgresult_get_this(self);
	VALUE error, exception, klass;
	char * sqlstate;

	if(this->pgresult == NULL)
	{
		PGconn *conn = pg_get_pgconn(this->connection);
		error = rb_str_new2( PQerrorMessage(conn) );
	}
	else
	{
		switch (PQresultStatus(this->pgresult))
		{
		case PGRES_TUPLES_OK:
		case PGRES_COPY_OUT:
		case PGRES_COPY_IN:
		case PGRES_COPY_BOTH:
		case PGRES_SINGLE_TUPLE:
		case PGRES_EMPTY_QUERY:
		case PGRES_COMMAND_OK:
			return self;
		case PGRES_BAD_RESPONSE:
		case PGRES_FATAL_ERROR:
		case PGRES_NONFATAL_ERROR:
			error = rb_str_new2( PQresultErrorMessage(this->pgresult) );
			break;
		default:
			error = rb_str_new2( "internal error : unknown result status." );
		}
	}

	PG_ENCODING_SET_NOCHECK( error, ENCODING_GET(self) );

	sqlstate = PQresultErrorField( this->pgresult, PG_DIAG_SQLSTATE );
	klass = lookup_error_class( sqlstate );
	exception = rb_exc_new3( klass, error );
	rb_iv_set( exception, "@connection", this->connection );
	rb_iv_set( exception, "@result", this->pgresult ? self : Qnil );
	rb_exc_raise( exception );

	/* Not reached */
	return self;
}

#clearnil

Clears the PG::Result object as the result of a query. This frees all underlying memory consumed by the result object. Afterwards access to result methods raises PG::Error “result has been cleared”.

Explicit calling #clear can lead to better memory performance, but is not generally necessary. Special care must be taken when PG::Tuple objects are used. In this case #clear must not be called unless all PG::Tuple objects of this result are fully materialized.

If PG::Result#autoclear? is true then the result is marked as cleared and the underlying C struct will be cleared automatically by libpq.

Returns:

  • (nil)

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# File 'ext/pg_result.c', line 268

VALUE
pg_result_clear(VALUE self)
{
	t_pg_result *this = pgresult_get_this(self);
	pgresult_clear( this );
	return Qnil;
}

#cleared?Boolean

Returns true if the backend result memory has been free'd.

Returns:

  • (Boolean)

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# File 'ext/pg_result.c', line 282

VALUE
pgresult_cleared_p( VALUE self )
{
	t_pg_result *this = pgresult_get_this(self);
	return this->pgresult ? Qfalse : Qtrue;
}

#cmd_statusString

Returns the status string of the last query command.

Returns:

  • (String)

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# File 'ext/pg_result.c', line 899

static VALUE
pgresult_cmd_status(VALUE self)
{
	VALUE ret = rb_tainted_str_new2(PQcmdStatus(pgresult_get(self)));
	PG_ENCODING_SET_NOCHECK(ret, ENCODING_GET(self));
	return ret;
}

#cmd_tuplesInteger Also known as: cmdtuples

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

If the SQL command that generated the PG::Result was not one of:

  • SELECT

  • CREATE TABLE AS

  • INSERT

  • UPDATE

  • DELETE

  • MOVE

  • FETCH

  • COPY

  • an EXECUTE of a prepared query that contains an INSERT, UPDATE, or DELETE statement

or if no tuples were affected, 0 is returned.

Returns:

  • (Integer)

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# File 'ext/pg_result.c', line 927

static VALUE
pgresult_cmd_tuples(VALUE self)
{
	long n;
	n = strtol(PQcmdTuples(pgresult_get(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_result.c', line 1084

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:


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# File 'ext/pg_result.c', line 1191

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

	RETURN_SIZED_ENUMERATOR(self, 0, NULL, pgresult_ntuples_for_enum);

	result = pgresult_get(self);

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

#each_row {|row| ... } ⇒ Object

Yields each row of the result. The row is a list of column values.

Yields:

  • (row)

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# File 'ext/pg_result.c', line 995

static VALUE
pgresult_each_row(VALUE self)
{
	t_pg_result *this;
	int row;
	int field;
	int num_rows;
	int num_fields;

	RETURN_SIZED_ENUMERATOR(self, 0, NULL, pgresult_ntuples_for_enum);

	this = pgresult_get_this_safe(self);
	num_rows = PQntuples(this->pgresult);
	num_fields = PQnfields(this->pgresult);

	for ( row = 0; row < num_rows; row++ ) {
		PG_VARIABLE_LENGTH_ARRAY(VALUE, row_values, num_fields, PG_MAX_COLUMNS)

		/* populate the row */
		for ( field = 0; field < num_fields; field++ ) {
			row_values[field] = this->p_typemap->funcs.typecast_result_value(this->p_typemap, self, row, field);
		}
		rb_yield( rb_ary_new4( num_fields, row_values ));
	}

	return Qnil;
}

#error_field(fieldcode) ⇒ String Also known as: result_error_field

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

An example:

begin
    conn.exec( "SELECT * FROM nonexistant_table" )
rescue PG::Error => err
    p [
        err.result.error_field( PG::Result::PG_DIAG_SEVERITY ),
        err.result.error_field( PG::Result::PG_DIAG_SQLSTATE ),
        err.result.error_field( PG::Result::PG_DIAG_MESSAGE_PRIMARY ),
        err.result.error_field( PG::Result::PG_DIAG_MESSAGE_DETAIL ),
        err.result.error_field( PG::Result::PG_DIAG_MESSAGE_HINT ),
        err.result.error_field( PG::Result::PG_DIAG_STATEMENT_POSITION ),
        err.result.error_field( PG::Result::PG_DIAG_INTERNAL_POSITION ),
        err.result.error_field( PG::Result::PG_DIAG_INTERNAL_QUERY ),
        err.result.error_field( PG::Result::PG_DIAG_CONTEXT ),
        err.result.error_field( PG::Result::PG_DIAG_SOURCE_FILE ),
        err.result.error_field( PG::Result::PG_DIAG_SOURCE_LINE ),
        err.result.error_field( PG::Result::PG_DIAG_SOURCE_FUNCTION ),
    ]
end

Outputs:

["ERROR", "42P01", "relation \"nonexistant_table\" does not exist", nil, nil,
 "15", nil, nil, nil, "path/to/parse_relation.c", "857", "parserOpenTable"]

Returns:

  • (String)

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# File 'ext/pg_result.c', line 538

static VALUE
pgresult_error_field(VALUE self, VALUE field)
{
	PGresult *result = pgresult_get( self );
	int fieldcode = NUM2INT( field );
	char * fieldstr = PQresultErrorField( result, fieldcode );
	VALUE ret = Qnil;

	if ( fieldstr ) {
		ret = rb_tainted_str_new2( fieldstr );
		PG_ENCODING_SET_NOCHECK( ret, ENCODING_GET(self ));
	}

	return ret;
}

#error_messageString Also known as: result_error_message

Returns the error message of the command as a string.

Returns:

  • (String)

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# File 'ext/pg_result.c', line 484

static VALUE
pgresult_error_message(VALUE self)
{
	VALUE ret = rb_tainted_str_new2(PQresultErrorMessage(pgresult_get(self)));
	PG_ENCODING_SET_NOCHECK(ret, ENCODING_GET(self));
	return ret;
}

#fformat(column_number) ⇒ Integer

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

Raises ArgumentError if column_number is out of range.

Returns:

  • (Integer)

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# File 'ext/pg_result.c', line 701

static VALUE
pgresult_fformat(VALUE self, VALUE column_number)
{
	PGresult *result = pgresult_get(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_result.c', line 1099

static VALUE
pgresult_field_values( VALUE self, VALUE field )
{
	PGresult *result = pgresult_get( self );
	const char *fieldname = StringValueCStr( 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 );
}

#fieldsArray

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

Returns:

  • (Array)

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# File 'ext/pg_result.c', line 1213

static VALUE
pgresult_fields(VALUE self)
{
	t_pg_result *this = pgresult_get_this_safe(self);

	if( this->nfields == -1 )
		pgresult_init_fnames( self );

	return rb_ary_new4( this->nfields, this->fnames );
}

#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_result.c', line 751

static VALUE
pgresult_fmod(VALUE self, VALUE column_number)
{
	PGresult *result = pgresult_get(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_result.c', line 590

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

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

	fname = rb_tainted_str_new2(PQfname(result, i));
	PG_ENCODING_SET_NOCHECK(fname, ENCODING_GET(self));
	return rb_obj_freeze(fname);
}

#fnumber(name) ⇒ Integer

Returns the index of the field specified by the string name. The given name is treated like an identifier in an SQL command, that is, it is downcased unless double-quoted. For example, given a query result generated from the SQL command:

result = conn.exec( %{SELECT 1 AS FOO, 2 AS "BAR"} )

we would have the results:

result.fname( 0 )            # => "foo"
result.fname( 1 )            # => "BAR"
result.fnumber( "FOO" )      # => 0
result.fnumber( "foo" )      # => 0
result.fnumber( "BAR" )      # => ArgumentError
result.fnumber( %{"BAR"} )   # => 1

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

Returns:

  • (Integer)

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# File 'ext/pg_result.c', line 629

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

	Check_Type(name, T_STRING);

	n = PQfnumber(pgresult_get(self), StringValueCStr(name));
	if (n == -1) {
		rb_raise(rb_eArgError,"Unknown field: %s", StringValueCStr(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_result.c', line 776

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

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

#ftable(column_number) ⇒ Integer

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:

  • (Integer)

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# File 'ext/pg_result.c', line 653

static VALUE
pgresult_ftable(VALUE self, VALUE column_number)
{
	Oid n ;
	int col_number = NUM2INT(column_number);
	PGresult *pgresult = pgresult_get(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 UINT2NUM(n);
}

#ftablecol(column_number) ⇒ Integer

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:

  • (Integer)

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# File 'ext/pg_result.c', line 677

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

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.

Returns:

  • (Integer)

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# File 'ext/pg_result.c', line 731

static VALUE
pgresult_ftype(VALUE self, VALUE index)
{
	PGresult* result = pgresult_get(self);
	int i = NUM2INT(index);
	if (i < 0 || i >= PQnfields(result)) {
		rb_raise(rb_eArgError, "invalid field number %d", i);
	}
	return UINT2NUM(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_result.c', line 819

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 = pgresult_get(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) ⇒ Integer

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

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

Returns:

  • (Integer)

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# File 'ext/pg_result.c', line 844

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 = pgresult_get(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_result.c', line 797

static VALUE
pgresult_getvalue(VALUE self, VALUE tup_num, VALUE field_num)
{
	t_pg_result *this = pgresult_get_this_safe(self);
	int i = NUM2INT(tup_num);
	int j = NUM2INT(field_num);

	if(i < 0 || i >= PQntuples(this->pgresult)) {
		rb_raise(rb_eArgError,"invalid tuple number %d", i);
	}
	if(j < 0 || j >= PQnfields(this->pgresult)) {
		rb_raise(rb_eArgError,"invalid field number %d", j);
	}
	return this->p_typemap->funcs.typecast_result_value(this->p_typemap, self, i, j);
}

#inspectObject

Return a String representation of the object suitable for debugging.


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# File 'lib/pg/result.rb', line 20

def inspect
	str = self.to_s
	str[-1,0] = if cleared?
		" cleared"
	else
		" status=#{res_status(result_status)} ntuples=#{ntuples} nfields=#{nfields} cmd_tuples=#{cmd_tuples}"
	end
	return str
end

#map_types!(type_map) ⇒ Object

Apply a type map for all value retrieving methods.

type_map: a PG::TypeMap instance.

See PG::BasicTypeMapForResults


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# File 'lib/pg/result.rb', line 13

def map_types!(type_map)
	self.type_map = type_map
	return self
end

#nfieldsInteger Also known as: num_fields

Returns the number of columns in the query result.

Returns:

  • (Integer)

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# File 'ext/pg_result.c', line 578

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

#nparamsInteger

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

Returns:

  • (Integer)

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# File 'ext/pg_result.c', line 868

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

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

#ntuplesInteger Also known as: num_tuples

Returns the number of tuples in the query result.

Returns:

  • (Integer)

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# File 'ext/pg_result.c', line 560

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

#oid_valueInteger

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

Returns:

  • (Integer)

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# File 'ext/pg_result.c', line 942

static VALUE
pgresult_oid_value(VALUE self)
{
	Oid n = PQoidValue(pgresult_get(self));
	if (n == InvalidOid)
		return Qnil;
	else
		return UINT2NUM(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_result.c', line 884

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

	result = pgresult_get(self);
	return UINT2NUM(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_result.c', line 470

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

#result_statusInteger

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

  • PGRES_COPY_BOTH

Returns:

  • (Integer)

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# File 'ext/pg_result.c', line 457

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

#stream_each {|tuple| ... } ⇒ Object

Invokes block for each tuple in the result set in single row mode.

This is a convenience method for retrieving all result tuples as they are transferred. It is an alternative to repeated calls of PG::Connection#get_result , but given that it avoids the overhead of wrapping each row into a dedicated result object, it delivers data in nearly the same speed as with ordinary results.

The base result must be in status PGRES_SINGLE_TUPLE. It iterates over all tuples until the status changes to PGRES_TUPLES_OK. A PG::Error is raised for any errors from the server.

Row description data does not change while the iteration. All value retrieval methods refer to only the current row. Result#ntuples returns 1 while the iteration and 0 after all tuples were yielded.

Example:

conn.send_query( "first SQL query; second SQL query" )
conn.set_single_row_mode
conn.get_result.stream_each do |row|
  # do something with each received row of the first query
end
conn.get_result.stream_each do |row|
  # do something with each received row of the second query
end
conn.get_result  # => nil   (no more results)

Available since PostgreSQL-9.2

Yields:


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# File 'ext/pg_result.c', line 1398

static VALUE
pgresult_stream_each(VALUE self)
{
	return pgresult_stream_any(self, yield_hash);
}

#stream_each_row {|row| ... } ⇒ Object

Yields each row of the result set in single row mode. The row is a list of column values.

This method works equally to #stream_each , but yields an Array of values.

Available since PostgreSQL-9.2

Yields:

  • (row)

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# File 'ext/pg_result.c', line 1416

static VALUE
pgresult_stream_each_row(VALUE self)
{
	return pgresult_stream_any(self, yield_array);
}

#stream_each_tuple {|tuple| ... } ⇒ Object

Yields each row of the result set in single row mode.

This method works equally to #stream_each , but yields a PG::Tuple object.

Available since PostgreSQL-9.2

Yields:


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# File 'ext/pg_result.c', line 1432

static VALUE
pgresult_stream_each_tuple(VALUE self)
{
	return pgresult_stream_any(self, yield_tuple);
}

#tuple(n) ⇒ PG::Tuple

Returns a PG::Tuple from the nth row of the result.

Returns:


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# File 'ext/pg_result.c', line 1154

static VALUE
pgresult_tuple(VALUE self, VALUE index)
{
	int tuple_num = NUM2INT( index );
	t_pg_result *this;
	int num_tuples;

	this = pgresult_get_this_safe(self);
	num_tuples = PQntuples(this->pgresult);

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

	if( this->field_map == Qnil ){
		int i;
		VALUE field_map = rb_hash_new();

		if( this->nfields == -1 )
			pgresult_init_fnames( self );

		for( i = 0; i < this->nfields; i++ ){
			rb_hash_aset(field_map, this->fnames[i], INT2FIX(i));
		}
		rb_obj_freeze(field_map);
		this->field_map = field_map;
	}

  return pg_tuple_new(self, tuple_num);
}

#tuple_values(n) ⇒ Array

Returns an Array of the field values from the nth row of the result.

Returns:

  • (Array)

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# File 'ext/pg_result.c', line 1120

static VALUE
pgresult_tuple_values(VALUE self, VALUE index)
{
	int tuple_num = NUM2INT( index );
	t_pg_result *this;
	int field;
	int num_tuples;
	int num_fields;

	this = pgresult_get_this_safe(self);
	num_tuples = PQntuples(this->pgresult);
	num_fields = PQnfields(this->pgresult);

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

	{
		PG_VARIABLE_LENGTH_ARRAY(VALUE, row_values, num_fields, PG_MAX_COLUMNS)

		/* populate the row */
		for ( field = 0; field < num_fields; field++ ) {
			row_values[field] = this->p_typemap->funcs.typecast_result_value(this->p_typemap, self, tuple_num, field);
		}
		return rb_ary_new4( num_fields, row_values );
	}
}

#type_mapObject

Returns the TypeMap that is currently set for type casts of result values to ruby objects.


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# File 'ext/pg_result.c', line 1262

static VALUE
pgresult_type_map_get(VALUE self)
{
	t_pg_result *this = pgresult_get_this(self);

	return this->typemap;
}

#type_map=(typemap) ⇒ Object

Set the TypeMap that is used for type casts of result values to ruby objects.

All value retrieval methods will respect the type map and will do the type casts from PostgreSQL's wire format to Ruby objects on the fly, according to the rules and decoders defined in the given typemap.

typemap must be a kind of PG::TypeMap .


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# File 'ext/pg_result.c', line 1237

static VALUE
pgresult_type_map_set(VALUE self, VALUE typemap)
{
	t_pg_result *this = pgresult_get_this(self);
	t_typemap *p_typemap;

	if ( !rb_obj_is_kind_of(typemap, rb_cTypeMap) ) {
		rb_raise( rb_eTypeError, "wrong argument type %s (expected kind of PG::TypeMap)",
				rb_obj_classname( typemap ) );
	}
	Data_Get_Struct(typemap, t_typemap, p_typemap);

	this->typemap = p_typemap->funcs.fit_to_result( typemap, self );
	this->p_typemap = DATA_PTR( this->typemap );

	return typemap;
}

#valuesArray

Returns all tuples as an array of arrays.

Returns:

  • (Array)

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# File 'ext/pg_result.c', line 1029

static VALUE
pgresult_values(VALUE self)
{
	t_pg_result *this = pgresult_get_this_safe(self);
	int row;
	int field;
	int num_rows = PQntuples(this->pgresult);
	int num_fields = PQnfields(this->pgresult);
	VALUE results = rb_ary_new2( num_rows );

	for ( row = 0; row < num_rows; row++ ) {
		PG_VARIABLE_LENGTH_ARRAY(VALUE, row_values, num_fields, PG_MAX_COLUMNS)

		/* populate the row */
		for ( field = 0; field < num_fields; field++ ) {
			row_values[field] = this->p_typemap->funcs.typecast_result_value(this->p_typemap, self, row, field);
		}
		rb_ary_store( results, row, rb_ary_new4( num_fields, row_values ) );
	}

	return results;
}