diff --git a/src/Bundle/ChillActivityBundle/Repository/ActivityACLAwareRepository.php b/src/Bundle/ChillActivityBundle/Repository/ActivityACLAwareRepository.php
index b8684a0a5..ae2c448e6 100644
--- a/src/Bundle/ChillActivityBundle/Repository/ActivityACLAwareRepository.php
+++ b/src/Bundle/ChillActivityBundle/Repository/ActivityACLAwareRepository.php
@@ -62,7 +62,7 @@ final class ActivityACLAwareRepository
         $metadataActivity = $this->em->getClassMetadata(Activity::class);
 
         $from = $this->getFromClauseCenter($args);
-        $where = $this->getWhereClause($context, $args);
+        [$where, $parameters] = $this->getWhereClause($context, $args);
 
         return [
            'id' => $metadataActivity->getTableName()
@@ -71,7 +71,8 @@ final class ActivityACLAwareRepository
            'date' => $metadataActivity->getTableName()
                 .'.'.$metadataActivity->getColumnName('date'),
            'FROM' => $from,
-           'WHERE' => $where
+           'WHERE' => $where,
+           'parameters' => $parameters
        ];
     }
 
diff --git a/src/Bundle/ChillActivityBundle/Timeline/TimelineActivityProvider.php b/src/Bundle/ChillActivityBundle/Timeline/TimelineActivityProvider.php
index 52e1027a8..ff1d9ffb3 100644
--- a/src/Bundle/ChillActivityBundle/Timeline/TimelineActivityProvider.php
+++ b/src/Bundle/ChillActivityBundle/Timeline/TimelineActivityProvider.php
@@ -29,13 +29,13 @@ use Symfony\Component\Security\Core\Role\Role;
 use Doctrine\ORM\Mapping\ClassMetadata;
 use Chill\PersonBundle\Entity\Person;
 use Chill\MainBundle\Entity\Scope;
+use Chill\ActivityBundle\Entity\Activity;
+use Chill\MainBundle\Timeline\TimelineSingleQuery;
 
 /**
  * Provide activity for inclusion in timeline
  *
- * @author Julien Fastré <julien.fastre@champs-libres.coop>
- * @author Champs Libres <info@champs-libres.coop>
- */
+*/
 class TimelineActivityProvider implements TimelineProviderInterface
 {
     
@@ -93,63 +93,37 @@ class TimelineActivityProvider implements TimelineProviderInterface
      */
     public function fetchQuery($context, array $args)
     {
-        //$this->checkContext($context);
-        //
         if ('center' === $context) {
-            return $this->aclAwareRepository->queryTimelineIndexer($context, $args);
+            return TimelineSingleQuery::fromArray($this->aclAwareRepository
+                ->queryTimelineIndexer($context, $args));
         }
         
-        $metadataActivity = $this->em->getClassMetadata('ChillActivityBundle:Activity');
-        
-        return array(
+        $metadataActivity = $this->em->getClassMetadata(Activity::class);
+
+        [$where, $parameters] =  $this->getWhereClauseForPerson($args['person']);
+        dump($where, $parameters);
+        return TimelineSingleQuery::fromArray([
            'id' => $metadataActivity->getTableName()
                 .'.'.$metadataActivity->getColumnName('id'),
            'type' => 'activity',
            'date' => $metadataActivity->getTableName()
                 .'.'.$metadataActivity->getColumnName('date'),
-           'FROM' => $this->getFromClause($metadataActivity, $metadataPerson),
-           'WHERE' => $this->getWhereClause($metadataActivity, $metadataPerson,
-                   $args['person'])
-        );
-    }
-
-    private function getFromClause(string $context)
-    {
-        switch ($context) {
-            case 'person': 
-                return $this->getFromClausePerson($metadataActivity, $metadataPerson);
-        }
-    }
-
-    private function getWhereClause(string $context, array $args)
-    {
-        switch ($context) {
-            case 'person': 
-                return $this->getWhereClause($args['person']);
-        }
-    }
-
-    /**
-     *
-     * @var $centers array|Center[]
-     */
-    private function getWhereClauseForCenter(array $centers)
-    {
-        $clause = "";
-        $role = new Role('CHILL_ACTIVITY_SEE');
-
-
+           'FROM' => $this->getFromClausePerson($args['person']),
+           'WHERE' => $where,
+           'parameters' => $parameters
+       ]);
     }
     
     private function getWhereClauseForPerson(Person $person)
     {
+        $parameters = [];
         $metadataActivity = $this->em->getClassMetadata('ChillActivityBundle:Activity');
+        $associationMapping = $metadataActivity->getAssociationMapping('person');
         $metadataPerson = $this->em->getClassMetadata('ChillPersonBundle:Person');
 
         $role = new Role('CHILL_ACTIVITY_SEE');
         $reachableCenters = $this->helper->getReachableCenters($this->user, 
                 $role);
-        $associationMapping = $metadataActivity->getAssociationMapping('person');
         
         if (count($reachableCenters) === 0) {
             return 'FALSE = TRUE';
@@ -157,31 +131,41 @@ class TimelineActivityProvider implements TimelineProviderInterface
         
         // we start with activities having the person_id linked to person 
         // (currently only context "person" is supported)
-        $whereClause = sprintf('%s = %d',
-                 $associationMapping['joinColumns'][0]['name'],
-                 $person->getId());
+        $whereClause = sprintf(' {activity.person_id} = ? ');
+        $parameters[] = $person->getId();
         
         // we add acl (reachable center and scopes)
-        $centerAndScopeLines = array();
+        $centerAndScopeClauses = [];
         foreach ($reachableCenters as $center) {
-            $reachablesScopesId = array_map(
-                    function(Scope $scope) { return $scope->getId(); },
-                    $this->helper->getReachableScopes($this->user, $role, 
-                        $person->getCenter())
-                );
-                    
-            $centerAndScopeLines[] = sprintf('(%s = %d AND %s IN (%s))',
-                    $metadataPerson->getTableName().'.'.
-                        $metadataPerson->getAssociationMapping('center')['joinColumns'][0]['name'],
-                    $center->getId(),
-                    $metadataActivity->getTableName().'.'.
-                        $metadataActivity->getAssociationMapping('scope')['joinColumns'][0]['name'],
-                    implode(',', $reachablesScopesId));
-            
+            $parameters[] = $center->getId();
+            $scopes_ids = [];
+            $reachableScopes =  $this->helper->getReachableScopes($this->user, $role, $person->getCenter());
+            foreach ($reachableScopes as $scope) {
+                $scopes_ids[] = '?'; 
+                $parameters[] = $scope->getId();
+            }
+            $centerAndScopeClauses[] = \strtr(
+                '( {person.center_id} = ? AND {activity.scope_id} IN ({scopes_ids})) ',
+                [
+                    '{scopes_ids}' => \implode(", ", $scopes_ids)
+                ]
+            );
         }
-        $whereClause .= ' AND ('.implode(' OR ', $centerAndScopeLines).')';
-        
-        return $whereClause;
+        $whereClause .= ' AND ('.\implode(' OR ', $centerAndScopeClauses).' ) ';
+
+        return [
+            \strtr(
+                $whereClause,
+                [
+                    '{activity.person_id}' => $associationMapping['joinColumns'][0]['name'],
+                    '{person.center_id}' => $metadataPerson->getTableName().'.'.
+                        $metadataPerson->getAssociationMapping('center')['joinColumns'][0]['name'],
+                    '{activity.scope_id}' => $metadataActivity->getTableName().'.'.
+                        $metadataActivity->getAssociationMapping('scope')['joinColumns'][0]['name'],
+                ]
+            ),
+            $parameters
+        ];
     }
     
     private function getFromClausePerson()
@@ -199,21 +183,6 @@ class TimelineActivityProvider implements TimelineProviderInterface
             ;
     }
     
-    private function getFromClauseCenter()
-    {
-        $metadataActivity = $this->em->getClassMetadata('ChillActivityBundle:Activity');
-        $metadataPerson = $this->em->getClassMetadata('ChillPersonBundle:Person');
-        $associationMapping = $metadataActivity->getAssociationMapping('person');
-        
-        return $metadataActivity->getTableName().' JOIN '
-            .$metadataPerson->getTableName().' ON '
-            .$metadataPerson->getTableName().'.'.
-                $associationMapping['joinColumns'][0]['referencedColumnName']
-            .' = '
-            .$associationMapping['joinColumns'][0]['name']
-            ;
-    }
-
     /**
      * 
      * {@inheritDoc}
diff --git a/src/Bundle/ChillMainBundle/Timeline/TimelineBuilder.php b/src/Bundle/ChillMainBundle/Timeline/TimelineBuilder.php
index 2e4102af6..bd1a4cc1a 100644
--- a/src/Bundle/ChillMainBundle/Timeline/TimelineBuilder.php
+++ b/src/Bundle/ChillMainBundle/Timeline/TimelineBuilder.php
@@ -201,10 +201,13 @@ class TimelineBuilder implements ContainerAwareInterface
     /**
      * return the SQL SELECT query as a string,
      *
-     * @return string
+     * @return array: first parameter is the sql string, second an array with parameters
      */
-    private function buildSelectQuery(array $data): array
+    private function buildSelectQuery($data): array
     {
+        return [$data->buildSql(), $data->getParameters()];
+
+        // dead code
         $parameters = [];
 
         $sql = sprintf(
diff --git a/src/Bundle/ChillMainBundle/Timeline/TimelineSingleQuery.php b/src/Bundle/ChillMainBundle/Timeline/TimelineSingleQuery.php
new file mode 100644
index 000000000..cf8dc085e
--- /dev/null
+++ b/src/Bundle/ChillMainBundle/Timeline/TimelineSingleQuery.php
@@ -0,0 +1,155 @@
+<?php
+
+namespace Chill\MainBundle\Timeline;
+
+
+class TimelineSingleQuery
+{
+    private ?string $id;
+
+    private ?string $date;
+
+    private ?string $key;
+
+    private ?string $from;
+
+    private ?string $where;
+
+    private array $parameters = [];
+
+    private bool $distinct = false;
+
+    public function __construct(
+        string $id = null,
+        string $date = null,
+        string $key = null,
+        string $from = null,
+        string $where = null,
+        array $parameters = []
+    ) {
+        $this->id = $id;
+        $this->date = $date;
+        $this->key = $key;
+        $this->from = $from;
+        $this->where = $where;
+        $this->parameters = $parameters;
+    }
+
+    public static function fromArray(array $a)
+    {
+        return new TimelineSingleQuery(
+            $a['id'],
+            $a['date'],
+            $a['type'] ?? $a['key'],
+            $a['FROM'] ?? $a['from'],
+            $a['WHERE'] ?? $a['where'],
+            $a['parameters']);
+    }
+
+    public function getId(): string
+    {
+        return $this->id;
+    }
+    
+    public function setId(string $id): self
+    {
+        $this->id = $id;
+    
+        return $this;
+    }
+
+    public function getDate(): string
+    {
+        return $this->date;
+    }
+    
+    public function setDate(string $date): self
+    {
+        $this->date = $date;
+    
+        return $this;
+    }
+
+    public function getKey(): string
+    {
+        return $this->key;
+    }
+    
+    public function setKey(string $key): self
+    {
+        $this->key = $key;
+    
+        return $this;
+    }
+
+    public function getFrom(): string
+    {
+        return $this->from;
+    }
+    
+    public function setFrom(string $from): self
+    {
+        $this->from = $from;
+    
+        return $this;
+    }
+
+    public function getWhere(): string
+    {
+        return $this->where;
+    }
+    
+    public function setWhere(string $where): self
+    {
+        $this->where = $where;
+    
+        return $this;
+    }
+
+    public function getParameters(): array
+    {
+        return $this->parameters;
+    }
+    
+    public function setParameters(array $parameters): self
+    {
+        $this->parameters = $parameters;
+    
+        return $this;
+    }
+
+    public function setDistinct(bool $distinct): self
+    {
+        $this->distinct = $distinct;
+
+        return $this;
+    }
+
+    public function isDistinct(): bool
+    {
+        return $this->distinct;
+    }
+
+    public function buildSql(): string
+    {
+        $parameters = [];
+
+        $sql = \strtr(
+                'SELECT {distinct} {id} AS id, '
+                . '{date} AS "date", '
+                . "'{key}' AS type "
+                . 'FROM {from} '
+                . 'WHERE {where}',
+                [
+                    '{distinct}' => $this->distinct ? 'DISTINCT' : '',
+                    '{id}' => $this->getId(),
+                    '{date}' => $this->getDate(),
+                    '{key}' => $this->getKey(),
+                    '{from}' => $this->getFrom(),
+                    '{where}' => $this->getWhere(),
+                ]
+            );
+
+        return $sql;
+    }
+}