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

3 files changed, 127 insertions, 143 deletions

diff --git a/app/SQL/install.sql.mysql.php b/app/SQL/install.sql.mysql.php
index 0f396f701..328e8acc0 100644
--- a/app/SQL/install.sql.mysql.php
+++ b/app/SQL/install.sql.mysql.php
@@ -1,20 +1,22 @@
 <?php
-define('SQL_CREATE_DB', 'CREATE DATABASE IF NOT EXISTS `%1$s` DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;');
+const SQL_CREATE_DB = <<<'SQL'
+CREATE DATABASE IF NOT EXISTS `%1$s` DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
+SQL;
 
-define('SQL_CREATE_TABLES', '
-CREATE TABLE IF NOT EXISTS `%1$scategory` (
+const SQL_CREATE_TABLES = <<<'SQL'
+CREATE TABLE IF NOT EXISTS `_category` (
 	`id` SMALLINT NOT NULL AUTO_INCREMENT,	-- v0.7
-	`name` VARCHAR(' . FreshRSS_DatabaseDAO::LENGTH_INDEX_UNICODE . ') NOT NULL,	-- Max index length for Unicode is 191 characters (767 bytes)
+	`name` VARCHAR(191) NOT NULL,	-- Max index length for Unicode is 191 characters (767 bytes) FreshRSS_DatabaseDAO::LENGTH_INDEX_UNICODE
 	PRIMARY KEY (`id`),
 	UNIQUE KEY (`name`)	-- v0.7
 ) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
 ENGINE = INNODB;
 
-CREATE TABLE IF NOT EXISTS `%1$sfeed` (
+CREATE TABLE IF NOT EXISTS `_feed` (
 	`id` SMALLINT NOT NULL AUTO_INCREMENT,	-- v0.7
 	`url` VARCHAR(511) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL,
 	`category` SMALLINT DEFAULT 0,	-- v0.7
-	`name` VARCHAR(' . FreshRSS_DatabaseDAO::LENGTH_INDEX_UNICODE . ') NOT NULL,
+	`name` VARCHAR(191) NOT NULL,
 	`website` VARCHAR(255) CHARACTER SET latin1 COLLATE latin1_bin,
 	`description` TEXT,
 	`lastUpdate` INT(11) DEFAULT 0,	-- Until year 2038
@@ -28,7 +30,7 @@ CREATE TABLE IF NOT EXISTS `%1$sfeed` (
 	`cache_nbEntries` INT DEFAULT 0,	-- v0.7
 	`cache_nbUnreads` INT DEFAULT 0,	-- v0.7
 	PRIMARY KEY (`id`),
-	FOREIGN KEY (`category`) REFERENCES `%1$scategory`(`id`) ON DELETE SET NULL ON UPDATE CASCADE,
+	FOREIGN KEY (`category`) REFERENCES `_category`(`id`) ON DELETE SET NULL ON UPDATE CASCADE,
 	UNIQUE KEY (`url`),	-- v0.7
 	INDEX (`name`),	-- v0.7
 	INDEX (`priority`),	-- v0.7
@@ -36,7 +38,7 @@ CREATE TABLE IF NOT EXISTS `%1$sfeed` (
 ) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
 ENGINE = INNODB;
 
-CREATE TABLE IF NOT EXISTS `%1$sentry` (
+CREATE TABLE IF NOT EXISTS `_entry` (
 	`id` BIGINT NOT NULL,	-- v0.7
 	`guid` VARCHAR(760) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL,	-- Maximum for UNIQUE is 767B
 	`title` VARCHAR(255) NOT NULL,
@@ -51,7 +53,7 @@ CREATE TABLE IF NOT EXISTS `%1$sentry` (
 	`id_feed` SMALLINT,	-- v0.7
 	`tags` VARCHAR(1023),
 	PRIMARY KEY (`id`),
-	FOREIGN KEY (`id_feed`) REFERENCES `%1$sfeed`(`id`) ON DELETE CASCADE ON UPDATE CASCADE,
+	FOREIGN KEY (`id_feed`) REFERENCES `_feed`(`id`) ON DELETE CASCADE ON UPDATE CASCADE,
 	UNIQUE KEY (`id_feed`,`guid`),	-- v0.7
 	INDEX (`is_favorite`),	-- v0.7
 	INDEX (`is_read`),	-- v0.7
@@ -60,11 +62,11 @@ CREATE TABLE IF NOT EXISTS `%1$sentry` (
 ) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
 ENGINE = INNODB;
 
-INSERT IGNORE INTO `%1$scategory` (id, name) VALUES(1, "%2$s");
-');
+INSERT IGNORE INTO `_category` (id, name) VALUES(1, "Uncategorized");
+SQL;
 
-define('SQL_CREATE_TABLE_ENTRYTMP', '
-CREATE TABLE IF NOT EXISTS `%1$sentrytmp` (	-- v1.7
+const SQL_CREATE_TABLE_ENTRYTMP = <<<'SQL'
+CREATE TABLE IF NOT EXISTS `_entrytmp` (	-- v1.7
 	`id` BIGINT NOT NULL,
 	`guid` VARCHAR(760) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL,
 	`title` VARCHAR(255) NOT NULL,
@@ -79,17 +81,18 @@ CREATE TABLE IF NOT EXISTS `%1$sentrytmp` (	-- v1.7
 	`id_feed` SMALLINT,
 	`tags` VARCHAR(1023),
 	PRIMARY KEY (`id`),
-	FOREIGN KEY (`id_feed`) REFERENCES `%1$sfeed`(`id`) ON DELETE CASCADE ON UPDATE CASCADE,
+	FOREIGN KEY (`id_feed`) REFERENCES `_feed`(`id`) ON DELETE CASCADE ON UPDATE CASCADE,
 	UNIQUE KEY (`id_feed`,`guid`),
 	INDEX (`date`)
 ) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
 ENGINE = INNODB;
 
-CREATE INDEX `entry_feed_read_index` ON `%1$sentry`(`id_feed`,`is_read`);	-- v1.7 Located here to be auto-added
-');
+-- v1.7 Located here to be auto-added
+CREATE INDEX `entry_feed_read_index` ON `_entry`(`id_feed`,`is_read`);
+SQL;
 
-define('SQL_CREATE_TABLE_TAGS', '
-CREATE TABLE IF NOT EXISTS `%1$stag` (	-- v1.12
+const SQL_CREATE_TABLE_TAGS = <<<'SQL'
+CREATE TABLE IF NOT EXISTS `_tag` (	-- v1.12
 	`id` SMALLINT NOT NULL AUTO_INCREMENT,
 	`name` VARCHAR(63) NOT NULL,
 	`attributes` TEXT,
@@ -98,47 +101,27 @@ CREATE TABLE IF NOT EXISTS `%1$stag` (	-- v1.12
 ) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
 ENGINE = INNODB;
 
-CREATE TABLE IF NOT EXISTS `%1$sentrytag` (	-- v1.12
+CREATE TABLE IF NOT EXISTS `_entrytag` (	-- v1.12
 	`id_tag` SMALLINT,
 	`id_entry` BIGINT,
 	PRIMARY KEY (`id_tag`,`id_entry`),
-	FOREIGN KEY (`id_tag`) REFERENCES `%1$stag`(`id`) ON DELETE CASCADE ON UPDATE CASCADE,
-	FOREIGN KEY (`id_entry`) REFERENCES `%1$sentry`(`id`) ON DELETE CASCADE ON UPDATE CASCADE,
+	FOREIGN KEY (`id_tag`) REFERENCES `_tag`(`id`) ON DELETE CASCADE ON UPDATE CASCADE,
+	FOREIGN KEY (`id_entry`) REFERENCES `_entry`(`id`) ON DELETE CASCADE ON UPDATE CASCADE,
 	INDEX (`id_entry`)
 ) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci
 ENGINE = INNODB;
-');
+SQL;
 
-define(
-	'SQL_INSERT_FEED',
-	'INSERT IGNORE INTO `%1$sfeed` (url, category, name, website, description, ttl)
-		VALUES(:url, 1, :name, :website, :description, 86400);'
-);
+const SQL_INSERT_FEED = <<<'SQL'
+INSERT IGNORE INTO `_feed` (url, category, name, website, description, ttl)
+	VALUES(:url, 1, :name, :website, :description, 86400);
+SQL;
 
-define('SQL_DROP_TABLES', 'DROP TABLE IF EXISTS `%1$sentrytag`, `%1$stag`, `%1$sentrytmp`, `%1$sentry`, `%1$sfeed`, `%1$scategory`');
+const SQL_DROP_TABLES = <<<'SQL'
+DROP TABLE IF EXISTS `_entrytag`, `_tag`, `_entrytmp`, `_entry`, `_feed`, `_category`;
+SQL;
 
-define('SQL_UPDATE_UTF8MB4', '
-ALTER DATABASE `%2$s` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;	-- v1.5.0
-
-ALTER TABLE `%1$scategory` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
-UPDATE `%1$scategory` SET name=SUBSTRING(name,1,' . FreshRSS_DatabaseDAO::LENGTH_INDEX_UNICODE . ') WHERE LENGTH(name) > ' . FreshRSS_DatabaseDAO::LENGTH_INDEX_UNICODE . ';
-ALTER TABLE `%1$scategory` MODIFY `name` VARCHAR(' . FreshRSS_DatabaseDAO::LENGTH_INDEX_UNICODE . ') CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL;
-OPTIMIZE TABLE `%1$scategory`;
-
-ALTER TABLE `%1$sfeed` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
-UPDATE `%1$sfeed` SET name=SUBSTRING(name,1,' . FreshRSS_DatabaseDAO::LENGTH_INDEX_UNICODE . ') WHERE LENGTH(name) > ' . FreshRSS_DatabaseDAO::LENGTH_INDEX_UNICODE . ';
-ALTER TABLE `%1$sfeed` MODIFY `name` VARCHAR(' . FreshRSS_DatabaseDAO::LENGTH_INDEX_UNICODE . ') CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL;
-ALTER TABLE `%1$sfeed` MODIFY `description` TEXT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
-OPTIMIZE TABLE `%1$sfeed`;
-
-ALTER TABLE `%1$sentry` CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
-ALTER TABLE `%1$sentry` MODIFY `title` VARCHAR(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NOT NULL;
-ALTER TABLE `%1$sentry` MODIFY `author` VARCHAR(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
-ALTER TABLE `%1$sentry` MODIFY `tags` VARCHAR(1023) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
-OPTIMIZE TABLE `%1$sentry`;
-');
-
-define('SQL_UPDATE_GUID_LATIN1_BIN', '	-- v1.12
-ALTER TABLE `%1$sentrytmp` MODIFY `guid` VARCHAR(760) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL;
-ALTER TABLE `%1$sentry` MODIFY `guid` VARCHAR(760) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL;
-');
+const SQL_UPDATE_GUID_LATIN1_BIN = <<<'SQL'
+ALTER TABLE `_entrytmp` MODIFY `guid` VARCHAR(760) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL;	-- v1.12
+ALTER TABLE `_entry` MODIFY `guid` VARCHAR(760) CHARACTER SET latin1 COLLATE latin1_bin NOT NULL;
+SQL;
diff --git a/app/SQL/install.sql.pgsql.php b/app/SQL/install.sql.pgsql.php
index ef08ca940..dfacc38e7 100644
--- a/app/SQL/install.sql.pgsql.php
+++ b/app/SQL/install.sql.pgsql.php
@@ -1,14 +1,15 @@
 <?php
-define('SQL_CREATE_DB', 'CREATE DATABASE "%1$s" ENCODING \'UTF8\';');
+const SQL_CREATE_DB = <<<'SQL'
+CREATE DATABASE "%1$s" ENCODING 'UTF8';
+SQL;
 
-global $SQL_CREATE_TABLES;
-$SQL_CREATE_TABLES = array(
-'CREATE TABLE IF NOT EXISTS "%1$scategory" (
+const SQL_CREATE_TABLES = <<<'SQL'
+CREATE TABLE IF NOT EXISTS `_category` (
 	"id" SERIAL PRIMARY KEY,
 	"name" VARCHAR(255) UNIQUE NOT NULL
-);',
+);
 
-'CREATE TABLE IF NOT EXISTS "%1$sfeed" (
+CREATE TABLE IF NOT EXISTS `_feed` (
 	"id" SERIAL PRIMARY KEY,
 	"url" VARCHAR(511) UNIQUE NOT NULL,
 	"category" SMALLINT DEFAULT 0,
@@ -25,13 +26,13 @@ $SQL_CREATE_TABLES = array(
 	"attributes" TEXT,	-- v1.11.0
 	"cache_nbEntries" INT DEFAULT 0,
 	"cache_nbUnreads" INT DEFAULT 0,
-	FOREIGN KEY ("category") REFERENCES "%1$scategory" ("id") ON DELETE SET NULL ON UPDATE CASCADE
-);',
-'CREATE INDEX "%1$sname_index" ON "%1$sfeed" ("name");',
-'CREATE INDEX "%1$spriority_index" ON "%1$sfeed" ("priority");',
-'CREATE INDEX "%1$skeep_history_index" ON "%1$sfeed" ("keep_history");',
+	FOREIGN KEY ("category") REFERENCES `_category` ("id") ON DELETE SET NULL ON UPDATE CASCADE
+);
+CREATE INDEX `_name_index` ON `_feed` ("name");
+CREATE INDEX `_priority_index` ON `_feed` ("priority");
+CREATE INDEX `_keep_history_index` ON `_feed` ("keep_history");
 
-'CREATE TABLE IF NOT EXISTS "%1$sentry" (
+CREATE TABLE IF NOT EXISTS `_entry` (
 	"id" BIGINT NOT NULL PRIMARY KEY,
 	"guid" VARCHAR(760) NOT NULL,
 	"title" VARCHAR(255) NOT NULL,
@@ -45,22 +46,21 @@ $SQL_CREATE_TABLES = array(
 	"is_favorite" SMALLINT NOT NULL DEFAULT 0,
 	"id_feed" SMALLINT,
 	"tags" VARCHAR(1023),
-	FOREIGN KEY ("id_feed") REFERENCES "%1$sfeed" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
+	FOREIGN KEY ("id_feed") REFERENCES `_feed` ("id") ON DELETE CASCADE ON UPDATE CASCADE,
 	UNIQUE ("id_feed","guid")
-);',
-'CREATE INDEX "%1$sis_favorite_index" ON "%1$sentry" ("is_favorite");',
-'CREATE INDEX "%1$sis_read_index" ON "%1$sentry" ("is_read");',
-'CREATE INDEX "%1$sentry_lastSeen_index" ON "%1$sentry" ("lastSeen");',
-
-'INSERT INTO "%1$scategory" (id, name)
-	SELECT 1, \'%2$s\'
-	WHERE NOT EXISTS (SELECT id FROM "%1$scategory" WHERE id = 1)
-	RETURNING nextval(\'"%1$scategory_id_seq"\');',
 );
+CREATE INDEX `_is_favorite_index` ON `_entry` ("is_favorite");
+CREATE INDEX `_is_read_index` ON `_entry` ("is_read");
+CREATE INDEX `_entry_lastSeen_index` ON `_entry` ("lastSeen");
+
+INSERT INTO `_category` (id, name)
+	SELECT 1, 'Uncategorized'
+	WHERE NOT EXISTS (SELECT id FROM `_category` WHERE id = 1)
+	RETURNING nextval('`_category_id_seq`');
+SQL;
 
-global $SQL_CREATE_TABLE_ENTRYTMP;
-$SQL_CREATE_TABLE_ENTRYTMP = array(
-'CREATE TABLE IF NOT EXISTS "%1$sentrytmp" (	-- v1.7
+const SQL_CREATE_TABLE_ENTRYTMP = <<<'SQL'
+CREATE TABLE IF NOT EXISTS `_entrytmp` (	-- v1.7
 	"id" BIGINT NOT NULL PRIMARY KEY,
 	"guid" VARCHAR(760) NOT NULL,
 	"title" VARCHAR(255) NOT NULL,
@@ -74,36 +74,37 @@ $SQL_CREATE_TABLE_ENTRYTMP = array(
 	"is_favorite" SMALLINT NOT NULL DEFAULT 0,
 	"id_feed" SMALLINT,
 	"tags" VARCHAR(1023),
-	FOREIGN KEY ("id_feed") REFERENCES "%1$sfeed" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
+	FOREIGN KEY ("id_feed") REFERENCES `_feed` ("id") ON DELETE CASCADE ON UPDATE CASCADE,
 	UNIQUE ("id_feed","guid")
-);',
-'CREATE INDEX "%1$sentrytmp_date_index" ON "%1$sentrytmp" ("date");',
-
-'CREATE INDEX "%1$sentry_feed_read_index" ON "%1$sentry" ("id_feed","is_read");',	//v1.7
 );
+CREATE INDEX `_entrytmp_date_index` ON `_entrytmp` ("date");
+
+-- v1.7
+CREATE INDEX `_entry_feed_read_index` ON `_entry` ("id_feed","is_read");
+SQL;
 
-global $SQL_CREATE_TABLE_TAGS;
-$SQL_CREATE_TABLE_TAGS = array(
-'CREATE TABLE IF NOT EXISTS "%1$stag" (	-- v1.12
+const SQL_CREATE_TABLE_TAGS = <<<'SQL'
+CREATE TABLE IF NOT EXISTS `_tag` (	-- v1.12
 	"id" SERIAL PRIMARY KEY,
 	"name" VARCHAR(63) UNIQUE NOT NULL,
 	"attributes" TEXT
-);',
-'CREATE TABLE IF NOT EXISTS "%1$sentrytag" (
+);
+CREATE TABLE IF NOT EXISTS `_entrytag` (
 	"id_tag" SMALLINT,
 	"id_entry" BIGINT,
 	PRIMARY KEY ("id_tag","id_entry"),
-	FOREIGN KEY ("id_tag") REFERENCES "%1$stag" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
-	FOREIGN KEY ("id_entry") REFERENCES "%1$sentry" ("id") ON DELETE CASCADE ON UPDATE CASCADE
-);',
-'CREATE INDEX "%1$sentrytag_id_entry_index" ON "%1$sentrytag" ("id_entry");',
+	FOREIGN KEY ("id_tag") REFERENCES `_tag` ("id") ON DELETE CASCADE ON UPDATE CASCADE,
+	FOREIGN KEY ("id_entry") REFERENCES `_entry` ("id") ON DELETE CASCADE ON UPDATE CASCADE
 );
+CREATE INDEX `_entrytag_id_entry_index` ON `_entrytag` ("id_entry");
+SQL;
 
-define(
-	'SQL_INSERT_FEED',
-	'INSERT INTO "%1$sfeed" (url, category, name, website, description, ttl)
-		SELECT :url::VARCHAR, 1, :name, :website, :description, 86400
-		WHERE NOT EXISTS (SELECT id FROM "%1$sfeed" WHERE url = :url);'
-);
+const SQL_INSERT_FEED = <<<'SQL'
+INSERT INTO `_feed` (url, category, name, website, description, ttl)
+	SELECT :url::VARCHAR, 1, :name, :website, :description, 86400
+		WHERE NOT EXISTS (SELECT id FROM `_feed` WHERE url = :url);
+SQL;
 
-define('SQL_DROP_TABLES', 'DROP TABLE IF EXISTS "%1$sentrytag", "%1$stag", "%1$sentrytmp", "%1$sentry", "%1$sfeed", "%1$scategory"');
+const SQL_DROP_TABLES = <<<'SQL'
+DROP TABLE IF EXISTS `_entrytag`, `_tag`, `_entrytmp`, `_entry`, `_feed`, `_category`;
+SQL;
diff --git a/app/SQL/install.sql.sqlite.php b/app/SQL/install.sql.sqlite.php
index 88de84358..81370ce56 100644
--- a/app/SQL/install.sql.sqlite.php
+++ b/app/SQL/install.sql.sqlite.php
@@ -1,13 +1,16 @@
 <?php
-global $SQL_CREATE_TABLES;
-$SQL_CREATE_TABLES = array(
-'CREATE TABLE IF NOT EXISTS `category` (
+const SQL_CREATE_DB = <<<'SQL'
+SELECT 1;	-- Do nothing for SQLite
+SQL;
+
+const SQL_CREATE_TABLES = <<<'SQL'
+CREATE TABLE IF NOT EXISTS `category` (
 	`id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
 	`name` VARCHAR(255) NOT NULL,
 	UNIQUE (`name`)
-);',
+);
 
-'CREATE TABLE IF NOT EXISTS `feed` (
+CREATE TABLE IF NOT EXISTS `feed` (
 	`id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
 	`url` VARCHAR(511) NOT NULL,
 	`category` SMALLINT DEFAULT 0,
@@ -26,12 +29,12 @@ $SQL_CREATE_TABLES = array(
 	`cache_nbUnreads` INT DEFAULT 0,
 	FOREIGN KEY (`category`) REFERENCES `category`(`id`) ON DELETE SET NULL ON UPDATE CASCADE,
 	UNIQUE (`url`)
-);',
-'CREATE INDEX IF NOT EXISTS feed_name_index ON `feed`(`name`);',
-'CREATE INDEX IF NOT EXISTS feed_priority_index ON `feed`(`priority`);',
-'CREATE INDEX IF NOT EXISTS feed_keep_history_index ON `feed`(`keep_history`);',
+);
+CREATE INDEX IF NOT EXISTS feed_name_index ON `feed`(`name`);
+CREATE INDEX IF NOT EXISTS feed_priority_index ON `feed`(`priority`);
+CREATE INDEX IF NOT EXISTS feed_keep_history_index ON `feed`(`keep_history`);
 
-'CREATE TABLE IF NOT EXISTS `entry` (
+CREATE TABLE IF NOT EXISTS `entry` (
 	`id` BIGINT NOT NULL,
 	`guid` VARCHAR(760) NOT NULL,
 	`title` VARCHAR(255) NOT NULL,
@@ -48,17 +51,16 @@ $SQL_CREATE_TABLES = array(
 	PRIMARY KEY (`id`),
 	FOREIGN KEY (`id_feed`) REFERENCES `feed`(`id`) ON DELETE CASCADE ON UPDATE CASCADE,
 	UNIQUE (`id_feed`,`guid`)
-);',
-'CREATE INDEX IF NOT EXISTS entry_is_favorite_index ON `entry`(`is_favorite`);',
-'CREATE INDEX IF NOT EXISTS entry_is_read_index ON `entry`(`is_read`);',
-'CREATE INDEX IF NOT EXISTS entry_lastSeen_index ON `entry`(`lastSeen`);',	//v1.1.1
-
-'INSERT OR IGNORE INTO `category` (id, name) VALUES(1, "%2$s");',
 );
+CREATE INDEX IF NOT EXISTS entry_is_favorite_index ON `entry`(`is_favorite`);
+CREATE INDEX IF NOT EXISTS entry_is_read_index ON `entry`(`is_read`);
+CREATE INDEX IF NOT EXISTS entry_lastSeen_index ON `entry`(`lastSeen`);	-- //v1.1.1
+
+INSERT OR IGNORE INTO `category` (id, name) VALUES(1, "Uncategorized");
+SQL;
 
-global $SQL_CREATE_TABLE_ENTRYTMP;
-$SQL_CREATE_TABLE_ENTRYTMP = array(
-'CREATE TABLE IF NOT EXISTS `entrytmp` (	-- v1.7
+const SQL_CREATE_TABLE_ENTRYTMP = <<<'SQL'
+CREATE TABLE IF NOT EXISTS `entrytmp` (	-- v1.7
 	`id` BIGINT NOT NULL,
 	`guid` VARCHAR(760) NOT NULL,
 	`title` VARCHAR(255) NOT NULL,
@@ -75,42 +77,40 @@ $SQL_CREATE_TABLE_ENTRYTMP = array(
 	PRIMARY KEY (`id`),
 	FOREIGN KEY (`id_feed`) REFERENCES `feed`(`id`) ON DELETE CASCADE ON UPDATE CASCADE,
 	UNIQUE (`id_feed`,`guid`)
-);',
-'CREATE INDEX IF NOT EXISTS entrytmp_date_index ON `entrytmp`(`date`);',
-
-'CREATE INDEX IF NOT EXISTS `entry_feed_read_index` ON `entry`(`id_feed`,`is_read`);',	//v1.7
 );
+CREATE INDEX IF NOT EXISTS entrytmp_date_index ON `entrytmp`(`date`);
+
+-- v1.7
+CREATE INDEX IF NOT EXISTS `entry_feed_read_index` ON `entry`(`id_feed`,`is_read`);
+SQL;
 
-global $SQL_CREATE_TABLE_TAGS;
-$SQL_CREATE_TABLE_TAGS = array(
-'CREATE TABLE IF NOT EXISTS `tag` (	-- v1.12
+const SQL_CREATE_TABLE_TAGS = <<<'SQL'
+CREATE TABLE IF NOT EXISTS `tag` (	-- v1.12
 	`id` INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
 	`name` VARCHAR(63) NOT NULL,
 	`attributes` TEXT,
 	UNIQUE (`name`)
-);',
-'CREATE TABLE IF NOT EXISTS `entrytag` (
+);
+CREATE TABLE IF NOT EXISTS `entrytag` (
 	`id_tag` SMALLINT,
 	`id_entry` BIGINT,
 	PRIMARY KEY (`id_tag`,`id_entry`),
 	FOREIGN KEY (`id_tag`) REFERENCES `tag` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
 	FOREIGN KEY (`id_entry`) REFERENCES `entry` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
-);',
-'CREATE INDEX entrytag_id_entry_index ON `entrytag` (`id_entry`);',
 );
+CREATE INDEX entrytag_id_entry_index ON `entrytag` (`id_entry`);
+SQL;
 
-define(
-	'SQL_INSERT_FEED',
-	'INSERT OR IGNORE INTO `feed` (url, category, name, website, description, ttl)
-		VALUES(:url, 1, :name, :website, :description, 86400);'
-);
+const SQL_INSERT_FEED = <<<'SQL'
+INSERT OR IGNORE INTO `feed` (url, category, name, website, description, ttl)
+	VALUES(:url, 1, :name, :website, :description, 86400);
+SQL;
 
-global $SQL_DROP_TABLES;
-$SQL_DROP_TABLES = [
-	'DROP TABLE IF EXISTS `entrytag`',
-	'DROP TABLE IF EXISTS `tag`',
-	'DROP TABLE IF EXISTS `entrytmp`',
-	'DROP TABLE IF EXISTS `entry`',
-	'DROP TABLE IF EXISTS `feed`',
-	'DROP TABLE IF EXISTS `category`',
-];
+const SQL_DROP_TABLES = <<<'SQL'
+DROP TABLE IF EXISTS `entrytag`;
+DROP TABLE IF EXISTS `tag`;
+DROP TABLE IF EXISTS `entrytmp`;
+DROP TABLE IF EXISTS `entry`;
+DROP TABLE IF EXISTS `feed`;
+DROP TABLE IF EXISTS `category`;
+SQL;