diff -u b/dynamic_entity_reference.services.yml b/dynamic_entity_reference.services.yml
--- b/dynamic_entity_reference.services.yml
+++ b/dynamic_entity_reference.services.yml
@@ -15,6 +15,9 @@
   mysql.dynamic_entity_reference.storage.create_column:
     class: Drupal\dynamic_entity_reference\Storage\IntColumnHandlerMySQL
     arguments: ['@database']
+  pgsql.dynamic_entity_reference.storage.create_column:
+    class: Drupal\dynamic_entity_reference\Storage\IntColumnHandlerPostgreSQL
+    arguments: ['@database']
   sqlite.dynamic_entity_reference.storage.create_column:
     class: Drupal\dynamic_entity_reference\Storage\IntColumnHandlerSQLite
     arguments: ['@database']
diff -u b/src/EventSubscriber/FieldStorageSubscriber.php b/src/EventSubscriber/FieldStorageSubscriber.php
--- b/src/EventSubscriber/FieldStorageSubscriber.php
+++ b/src/EventSubscriber/FieldStorageSubscriber.php
@@ -7,11 +7,10 @@
 use Drupal\Core\Entity\EntityTypeEvents;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Drupal\Core\Entity\Sql\SqlEntityStorageInterface;
-use Drupal\Core\Entity\Sql\TableMappingInterface;
 use Drupal\Core\Field\FieldStorageDefinitionEvent;
 use Drupal\Core\Field\FieldStorageDefinitionEvents;
 use Drupal\Core\Field\FieldStorageDefinitionInterface;
-use Drupal\dynamic_entity_reference\Storage\IntColumnHandler;
+use Drupal\dynamic_entity_reference\Storage\IntColumnHandlerInterface;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
 /**
@@ -44,7 +43,7 @@
    * @param \Drupal\dynamic_entity_reference\Storage\IntColumnHandler $int_column_handler
    *   The integer column handler.
    */
-  public function __construct(EntityTypeManagerInterface $entity_type_manager, EntityFieldManagerInterface $entity_field_manager, IntColumnHandler $int_column_handler) {
+  public function __construct(EntityTypeManagerInterface $entity_type_manager, EntityFieldManagerInterface $entity_field_manager, IntColumnHandlerInterface $int_column_handler) {
     $this->entityTypeManager = $entity_type_manager;
     $this->entityFieldManager = $entity_field_manager;
     $this->intColumnHandler = $int_column_handler;
diff -u b/src/Storage/IntColumnHandler.php b/src/Storage/IntColumnHandler.php
--- b/src/Storage/IntColumnHandler.php
+++ b/src/Storage/IntColumnHandler.php
@@ -7,7 +7,7 @@
 /**
  * Per database implementation of denormalizing into integer columns.
  */
-class IntColumnHandler {
+class IntColumnHandler implements IntColumnHandlerInterface {
 
   /**
    * @var \Drupal\Core\Database\Connection
@@ -29,7 +29,6 @@
    *   The DER target_id columns.
    */
   public function create($table, array $columns) {
-    $this->createStart($table);
     $schema = $this->connection->schema();
     // The integer column specification.
     $spec = [
@@ -62,11 +61,6 @@
         $this->createTrigger($trigger, $op, $prefixed_name, $body);
       }
     }
-    $this->createEnd();
-  }
-
-  protected function createStart($table) {
-
   }
 
   /**
@@ -82,7 +76,6 @@
     throw new \LogicException('Not implemented');
   }
 
-
   /**
    * Actually create the trigger.
    *
@@ -97,14 +90,6 @@
   }
 
   /**
-   * We are done.
-   */
-  protected function createEnd() {
-
-  }
-
-
-  /**
    * @TODO
    *
    * @param $table
diff -u b/src/Storage/IntColumnHandlerMySQL.php b/src/Storage/IntColumnHandlerMySQL.php
--- b/src/Storage/IntColumnHandlerMySQL.php
+++ b/src/Storage/IntColumnHandlerMySQL.php
@@ -4,20 +4,10 @@
 
 class IntColumnHandlerMySQL extends IntColumnHandler {
 
-  protected function createStart($table) {
-    // MySQL does not have transactional DDL so before executing many DDL
-    // statements it is safest to lock the table.
-    $this->connection->query('LOCK TABLES {' . $table . '} WRITE');
-  }
-
   protected function createBody($column_int, $column) {
     return "NEW.$column_int = CAST(NEW.$column AS UNSIGNED)";
   }
 
-  protected function createEnd() {
-    $this->connection->query('UNLOCK TABLES');
-  }
-
   protected function createTrigger($trigger, $op, $prefixed_name, $body) {
     $this->connection->query("CREATE TRIGGER $trigger BEFORE $op ON $prefixed_name FOR EACH ROW SET $body");
   }
diff -u b/src/Storage/IntColumnHandlerSQLite.php b/src/Storage/IntColumnHandlerSQLite.php
--- b/src/Storage/IntColumnHandlerSQLite.php
+++ b/src/Storage/IntColumnHandlerSQLite.php
@@ -23,14 +23,18 @@
    */
   protected function createTrigger($trigger, $op, $prefixed_name, $body) {
     $parts = explode('.', $prefixed_name);
+    // Simpletest for example prefixes with a database name but SQLite does
+    // not support referencing databases in the body of the trigger (even if it
+    // is the same database the triggering table is in). 
     $table_name = array_pop($parts);
     $query = "
-        CREATE TRIGGER $trigger 
-        AFTER $op 
-        ON $prefixed_name 
-        FOR EACH ROW 
-        BEGIN 
+        CREATE TRIGGER $trigger AFTER $op ON $prefixed_name
+        FOR EACH ROW
+        BEGIN
           UPDATE $table_name SET $body WHERE ROWID=NEW.ROWID";
+    // SQLite requires a ; in the query which requires bypassing Drupal's built
+    // in single statement only protection. Although this method is not
+    // supposed to be called by user submitted data, 
     if (strpos($query, ';') !== FALSE) {
       throw new \InvalidArgumentException('; is not supported in SQL strings. Use only one statement at a time.');
     }
only in patch2:
unchanged:
--- /dev/null
+++ b/dynamic_entity_reference.install
@@ -0,0 +1,13 @@
+<?php
+
+/**
+ * Change target_id to string.
+ */
+function dynamic_entity_reference_update_8000() {
+  $update_manager = \Drupal::entityDefinitionUpdateManager();
+  /** @var \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager */
+  $entity_field_manager = \Drupal::service('entity_field.manager');
+  foreach ($entity_field_manager->getFieldMapByFieldType('dynamic_entity_reference') as $entity_type_id => $map) {
+    array_map([$update_manager, 'updateFieldStorageDefinition'], array_intersect_key($entity_field_manager->getFieldStorageDefinitions($entity_type_id), $map));
+  }
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/src/Storage/IntColumnHandlerInterface.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Drupal\dynamic_entity_reference\Storage;
+
+
+interface IntColumnHandlerInterface {
+
+  /**
+   * Create the _int columns and the triggers for them.
+   *
+   * @param $table
+   *   The non-prefix table to operate on.
+   * @param array $columns
+   *   The DER target_id columns.
+   */
+  public function create($table, array $columns);
+
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/src/Storage/IntColumnHandlerPostgreSQL.php
@@ -0,0 +1,79 @@
+<?php
+
+
+namespace Drupal\dynamic_entity_reference\Storage;
+
+use Drupal\Core\Database\Connection;
+
+class IntColumnHandlerPostgreSQL implements IntColumnHandlerInterface {
+
+  /**
+   * @var \Drupal\Core\Database\Connection
+   */
+  protected $connection;
+
+  public function __construct(Connection $connection) {
+    $this->connection = $connection;
+  }
+
+  /**
+   * Create the _int columns and the triggers for them.
+   *
+   * This is common for SQLite and MySQL.
+   *
+   * @param $table
+   *   The non-prefix table to operate on.
+   * @param array $columns
+   *   The DER target_id columns.
+   */
+  public function create($table, array $columns) {
+    $schema = $this->connection->schema();
+    // The integer column specification.
+    $spec = [
+      'type' => 'int',
+      'unsigned' => TRUE,
+      'not null' => FALSE,
+    ];
+    foreach ($columns as $column) {
+      $column_int = $column . '_int';
+      // Make sure the integer columns exist.
+      if (!$schema->fieldExists($table, $column_int)) {
+        $this->createTriggerFunction($table, $column, $column_int);
+        $this->createTrigger($table, $column, $column_int);
+        $schema->addField($table, $column_int, $spec);
+      }
+    }
+  }
+
+  protected function createTriggerFunction($table, $column, $column_int) {
+    $function_name = $this->getFunctionName($table, $column_int);
+    $query = "CREATE FUNCTION $function_name() RETURNS trigger AS $$
+      BEGIN
+        NEW.$column_int = (CASE WHEN NEW.$column ~ '^[0-9]+$' THEN NEW.$column ELSE '0' END)::integer";
+    if (strpos($query, ';') !== FALSE) {
+      throw new \InvalidArgumentException('; is not supported in SQL strings. Use only one statement at a time.');
+    }
+    $this->connection->query("$query; RETURN NEW; END; $$ LANGUAGE plpgsql IMMUTABLE RETURNS NULL ON NULL INPUT", [], ['allow_delimiter_in_query' => TRUE]);
+  }
+
+  protected function createTrigger($table, $column, $column_int) {
+    $function_name = $this->getFunctionName($table, $column_int);
+    $this->connection->query("
+      CREATE TRIGGER $function_name
+        BEFORE INSERT OR UPDATE
+        ON {" . "$table}
+        FOR EACH ROW
+        EXECUTE PROCEDURE $function_name();      
+    ");
+  }
+
+  /**
+   * @param $table
+   * @param $column_int
+   * @return string
+   */
+  protected function getFunctionName($table, $column_int) {
+    return implode('_', [$this->connection->prefixTables('{' . $table . '}'), $column_int]);
+  }
+
+}