diff --git a/classes/Oauth_application.php b/classes/Oauth_application.php
index ed838d0602..aa43038806 100644
--- a/classes/Oauth_application.php
+++ b/classes/Oauth_application.php
@@ -190,7 +190,7 @@ class Oauth_application extends Managed_DataObject
                 'type' => array('type' => 'int', 'size' => 'tiny', 'default' => 0, 'description' => 'type of app, 1 = browser, 2 = desktop'),
                 'access_type' => array('type' => 'int', 'size' => 'tiny', 'default' => 0, 'description' => 'default access type, bit 1 = read, bit 2 = write'),
                 'created' => array('type' => 'datetime', 'description' => 'date this record was created'),
-                'modified' => array('type' => 'datetime', 'not null' => true, 'description' => 'date this record was modified'),
+                'modified' => array('type' => 'timestamp', 'not null' => true, 'description' => 'date this record was modified'),
             ),
             'primary key' => array('id'),
             'unique keys' => array(
diff --git a/lib/database/mysqlschema.php b/lib/database/mysqlschema.php
index 41235f89f5..9c6cf0e01d 100644
--- a/lib/database/mysqlschema.php
+++ b/lib/database/mysqlschema.php
@@ -461,7 +461,7 @@ class MysqlSchema extends Schema
             $phrase[] = "ENGINE '{$engine}'";
         }
         if (strtolower($oldProps['TABLE_COLLATION']) !== "{$charset}_bin") {
-            $phrase[] = "CONVERT TO CHARACTER SET '{$charset} COLLATE '{$charset}_bin'";
+            $phrase[] = "CONVERT TO CHARACTER SET '{$charset}' COLLATE '{$charset}_bin'";
             $phrase[] = "DEFAULT CHARACTER SET '{$charset}'";
             $phrase[] = "DEFAULT COLLATE '{$charset}_bin'";
         }
diff --git a/lib/database/pgsqlschema.php b/lib/database/pgsqlschema.php
index 5cf9aad5eb..3c2ab76ef2 100644
--- a/lib/database/pgsqlschema.php
+++ b/lib/database/pgsqlschema.php
@@ -328,7 +328,8 @@ class PgsqlSchema extends Schema
     {
         $data = $this->fetchQueryData(
             <<<END
-            SELECT "cols"."attname" AS "col", "con"."consrc" AS "check"
+            SELECT "cols"."attname" AS "col",
+                pg_get_expr("con"."conbin", "con"."conrelid") AS "check"
               FROM pg_constraint AS "con"
               INNER JOIN pg_attribute AS "cols"
               ON "con"."conrelid" = "cols"."attrelid"
diff --git a/lib/database/schema.php b/lib/database/schema.php
index 9d010c4a56..a5cf4568b7 100644
--- a/lib/database/schema.php
+++ b/lib/database/schema.php
@@ -878,7 +878,7 @@ class Schema
     {
         // MDB2_Driver_Common::quote changes empty strings to "NULL".
         if ($val === '') {
-            return '';
+            return "''";
         }
         return $this->conn->quote($val);
     }
diff --git a/lib/modules/Realtime/classes/Realtime_channel.php b/lib/modules/Realtime/classes/Realtime_channel.php
index 00ca056fe0..3178380e5d 100644
--- a/lib/modules/Realtime/classes/Realtime_channel.php
+++ b/lib/modules/Realtime/classes/Realtime_channel.php
@@ -85,7 +85,7 @@ class Realtime_channel extends Managed_DataObject
                 'created' => ['type' => 'datetime',
                     'not null' => true,
                     'description' => 'date this record was created'],
-                'modified' => ['type' => 'datetime',
+                'modified' => ['type' => 'timestamp',
                     'not null' => true,
                     'description' => 'date this record was modified'],
             ],
diff --git a/lib/util/daemon.php b/lib/util/daemon.php
index c7d8329412..8798ae52a4 100644
--- a/lib/util/daemon.php
+++ b/lib/util/daemon.php
@@ -78,12 +78,12 @@ class Daemon
 
     public function background()
     {
-        // Database connection will likely get lost after forking
+        // Database connection will be likely lost after forking.
         $this->resetDb();
 
         // Double-forking.
         foreach (['single', 'double'] as $v) {
-            switch ($pid = pcntl_fork()) {
+            switch (($pid = pcntl_fork())) {
                 case -1: // error
                     common_log(LOG_ERR, 'Could not fork.');
                     return false;
diff --git a/plugins/EmailSummary/classes/Email_summary_status.php b/plugins/EmailSummary/classes/Email_summary_status.php
index 1e8d7898f1..4737d697e6 100644
--- a/plugins/EmailSummary/classes/Email_summary_status.php
+++ b/plugins/EmailSummary/classes/Email_summary_status.php
@@ -44,7 +44,7 @@ class Email_summary_status extends Managed_DataObject
     public $send_summary;                    // bool    not_null default_true
     public $last_summary_id;                 // int(4)  null
     public $created;                         // datetime not_null
-    public $modified;                        // datetime not_null
+    public $modified;                        // timestamp not_null
 
     public static function schemaDef()
     {
diff --git a/plugins/Poll/classes/User_poll_prefs.php b/plugins/Poll/classes/User_poll_prefs.php
index cf3272e2bc..9ee591055a 100644
--- a/plugins/Poll/classes/User_poll_prefs.php
+++ b/plugins/Poll/classes/User_poll_prefs.php
@@ -41,7 +41,7 @@ class User_poll_prefs extends Managed_DataObject
     public $user_id;          // int id
     public $hide_responses;   // bool
     public $created;          // datetime
-    public $modified;         // datetime
+    public $modified;         // timestamp
 
     /**
      * The One True Thingy that must be defined and declared.