PDO refactoring for code simplification (#2522)

* PDO refactor

* Automatic prefix when using the syntax `_tableName`
* Uniformity: MySQL is now PDO::ATTR_EMULATE_PREPARES = false just like SQLite and PostgreSQL, with consequences such as only one statement per query
* Use PDO methods exec(), query(), prepare() + execute() in a more efficient way
* Remove auto-update SQL code for versions older than FreshRSS 1.5 (3 years old)
* The name of the default category is set in PHP instead of in the DB (simplies SQL and allows changing the name according to the FreshRSS language)
* Rename `->bd` to `->pdo` (less of a frenshism, and more informative)
* Fix some requests, which were not compatible with MySQL prepared statements

* Whitespace

* Fix syntax for PostgreSQL sequences

+ MySQL install

* Minor formatting

* Fix lastInsertId for PostgreSQL

* Use PHP 5.6+ const

Take advantage of https://github.com/FreshRSS/FreshRSS/pull/2527
https://www.php.net/manual/en/migration56.new-features.php

* A bit of forgotten PHP 5.6 simplification for cURL

* Forgotten $s

* Mini fix custom user config

https://github.com/FreshRSS/FreshRSS/pull/2490/files#r326290346

* More work on install.php but not finished

* install.php working

* More cleaning of PDO in install

* Even more simplification

Take advantage of PDO->exec() to run multiple statements

* Disallow changing the name of the default category

https://github.com/FreshRSS/FreshRSS/pull/2522#discussion_r326967724

1 files changed, 2 insertions, 3 deletions

diff --git a/app/Models/StatsDAOPGSQL.php b/app/Models/StatsDAOPGSQL.php
index 1effbb64b..4a66068cb 100644
--- a/app/Models/StatsDAOPGSQL.php
+++ b/app/Models/StatsDAOPGSQL.php
@@ -47,14 +47,13 @@ class FreshRSS_StatsDAOPGSQL extends FreshRSS_StatsDAO {
 		$sql = <<<SQL
 SELECT extract( {$period} from to_timestamp(e.date)) AS period
 , COUNT(1) AS count
-FROM "{$this->prefix}entry" AS e
+FROM `_entry` AS e
 {$restrict}
 GROUP BY period
 ORDER BY period ASC
 SQL;
 
-		$stm = $this->bd->prepare($sql);
-		$stm->execute();
+		$stm = $this->pdo->query($sql);
 		$res = $stm->fetchAll(PDO::FETCH_NAMED);
 
 		foreach ($res as $value) {