Add PHPDoc about boolean values in scalar() and queryScalar()

[Tigrov]

Q	A
Is bugfix?	❌
New feature?	❌
Breaks BC?	❌
Fixed issues	#851

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.70%. Comparing base (98eed39) to head (1cfe760).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #918   +/-   ##
=========================================
  Coverage     99.70%   99.70%           
  Complexity     1498     1498           
=========================================
  Files            81       81           
  Lines          3702     3702           
=========================================
  Hits           3691     3691           
  Misses           11       11           

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[vjik]

Suggest to add scalar $default = null parameter. This allow to use this methods for boolean values also.

[Tigrov]

How to use it?

Field of boolean type can return true, false and null values.

[vjik]

How to use it?

Field of boolean type can return true, false and null values.

When I know that result bool|null, I can use ->queryScalar('') code. When returns empty string - value doesn't exist.

[Tigrov]

Good idea, but it uses PDOStatement::fetchColumn() and the method returns false for both: no results and false value result

db/src/Driver/Pdo/AbstractPdoCommand.php

Lines 251 to 253 in 98eed39

	} elseif ($this->is($queryMode, self::QUERY_MODE_SCALAR)) {
	/** @psalm-var mixed $result */
	$result = $this->pdoStatement?->fetchColumn();

From the documentation https://www.php.net/manual/en/pdostatement.fetchcolumn.php

Note:
PDOStatement::fetchColumn() should not be used to retrieve boolean columns, as it is impossible to distinguish a value of false from there being no more rows to retrieve. Use PDOStatement::fetch() instead.

[vjik]

Good idea, but it uses PDOStatement::fetchColumn() and the method returns false for both: no results and false value result

So in this case my suggestion doesn't matter.