diff --git a/php/src/db/Capacitor.php b/php/src/db/Capacitor.php
index 6dfa4e9..8fb2403 100644
--- a/php/src/db/Capacitor.php
+++ b/php/src/db/Capacitor.php
@@ -30,6 +30,11 @@ class Capacitor implements ITransactor {
     return $this->getStorage()->db();
   }
 
+  function ensureLive(): self {
+    $this->getStorage()->ensureLive();
+    return $this;
+  }
+
   /** @var CapacitorChannel */
   protected $channel;
 
diff --git a/php/src/db/CapacitorChannel.php b/php/src/db/CapacitorChannel.php
index 3489203..b438499 100644
--- a/php/src/db/CapacitorChannel.php
+++ b/php/src/db/CapacitorChannel.php
@@ -420,6 +420,11 @@ class CapacitorChannel implements ITransactor {
     return $this;
   }
 
+  function ensureLive(): self {
+    $this->capacitor->ensureLive();
+    return $this;
+  }
+
   function willUpdate(...$transactors): ITransactor {
     return $this->capacitor->willUpdate(...$transactors);
   }
diff --git a/php/src/db/CapacitorStorage.php b/php/src/db/CapacitorStorage.php
index f529839..dbc7f87 100644
--- a/php/src/db/CapacitorStorage.php
+++ b/php/src/db/CapacitorStorage.php
@@ -16,7 +16,12 @@ use Traversable;
 abstract class CapacitorStorage {
   abstract function db(): IDatabase;
 
-    /** @var CapacitorChannel[] */
+  function ensureLive(): self {
+    $this->db()->ensure();
+    return $this;
+  }
+
+  /** @var CapacitorChannel[] */
   protected $channels;
 
   function addChannel(CapacitorChannel $channel): CapacitorChannel {
diff --git a/php/src/db/IDatabase.php b/php/src/db/IDatabase.php
index 8e04bab..32a0013 100644
--- a/php/src/db/IDatabase.php
+++ b/php/src/db/IDatabase.php
@@ -11,6 +11,14 @@ interface IDatabase extends ITransactor {
   /** obtenir la requête SQL correspondant à $query */
   function getSql($query, ?array $params=null): string;
 
+  /**
+   * vérifier la connexion à la base de données, et refaire la connexion si
+   * nécessaire. NB: si la connexion a la base de données était perdue, les
+   * transactions en cours sont perdues. cette méthode est donc prévue pour
+   * vérifier la validité de la connexion avant de lancer une transaction
+   */
+  function ensure(): self;
+
   /**
    * - si c'est un insert, retourner l'identifiant autogénéré de la ligne
    * - sinon retourner le nombre de lignes modifiées en cas de succès, ou false
diff --git a/php/src/db/pdo/Pdo.php b/php/src/db/pdo/Pdo.php
index d06f5dd..fc324dc 100644
--- a/php/src/db/pdo/Pdo.php
+++ b/php/src/db/pdo/Pdo.php
@@ -120,8 +120,8 @@ class Pdo implements IDatabase {
     return $query->getSql();
   }
 
-  function open(): self {
-    if ($this->db === null) {
+  function open(bool $reopen=false): self {
+    if ($this->db === null || $reopen) {
       $dbconn = $this->dbconn;
       $options = $this->options;
       if (is_callable($options)) {
@@ -134,6 +134,17 @@ class Pdo implements IDatabase {
     return $this;
   }
 
+  const SQL_CHECK_LIVE = "select 1";
+
+  function ensure(): self {
+    try {
+      $this->_exec(static::SQL_CHECK_LIVE);
+    } catch (\PDOException $e) {
+      $this->open(true);
+    }
+    return $this;
+  }
+
   function close(): void {
     $this->db = null;
   }
diff --git a/php/src/db/pgsql/Pgsql.php b/php/src/db/pgsql/Pgsql.php
index 963d425..deeebac 100644
--- a/php/src/db/pgsql/Pgsql.php
+++ b/php/src/db/pgsql/Pgsql.php
@@ -138,8 +138,8 @@ class Pgsql implements IDatabase {
     return $query->getSql();
   }
 
-  function open(): self {
-    if ($this->db === null) {
+  function open(bool $reopen=false): self {
+    if ($this->db === null || $reopen) {
       $dbconn = $this->dbconn;
       $connection_string = [$dbconn[""] ?? null];
       unset($dbconn[""]);
@@ -173,6 +173,17 @@ class Pgsql implements IDatabase {
     return $this;
   }
 
+  const SQL_CHECK_LIVE = "select 1";
+
+  function ensure(): self {
+    try {
+      $this->_exec(static::SQL_CHECK_LIVE);
+    } catch (\PDOException $e) {
+      $this->open(true);
+    }
+    return $this;
+  }
+
   function close(): self {
     if ($this->db !== null) {
       pg_close($this->db);
diff --git a/php/src/db/sqlite/Sqlite.php b/php/src/db/sqlite/Sqlite.php
index 443d995..ece4379 100644
--- a/php/src/db/sqlite/Sqlite.php
+++ b/php/src/db/sqlite/Sqlite.php
@@ -157,8 +157,8 @@ class Sqlite implements IDatabase {
     return $query->getSql();
   }
 
-  function open(): self {
-    if ($this->db === null) {
+  function open(bool $reopen=false): self {
+    if ($this->db === null || $reopen) {
       $this->db = new SQLite3($this->file, $this->flags, $this->encryptionKey);
       _config::with($this->config)->configure($this);
       _sqliteMigration::with($this->migration)->migrate($this);
@@ -167,6 +167,17 @@ class Sqlite implements IDatabase {
     return $this;
   }
 
+  const SQL_CHECK_LIVE = "select 1";
+
+  function ensure(): self {
+    try {
+      $this->_exec(static::SQL_CHECK_LIVE);
+    } catch (\PDOException $e) {
+      $this->open(true);
+    }
+    return $this;
+  }
+
   function close(): void {
     if ($this->db !== null) {
       $this->db->close();