NEW: Allow 'null' limit in database queries

_config/connectors.yml

@@ -7,10 +7,10 @@ Injector:
     properties:
       connector: %$PDOConnector
       schemaManager: %$PostgreSQLSchemaManager
-      queryBuilder: %$DBQueryBuilder
+      queryBuilder: %$PostgreSQLQueryBuilder
   PostgreSQLDatabase:
     class: 'PostgreSQLDatabase'
     properties:
       connector: %$PostgreSQLConnector
       schemaManager: %$PostgreSQLSchemaManager
-      queryBuilder: %$DBQueryBuilder
+      queryBuilder: %$PostgreSQLQueryBuilder

code/PostgreSQLQueryBuilder.php

@@ -0,0 +1,42 @@
+<?php
+
+class PostgreSQLQueryBuilder extends DBQueryBuilder {
+
+	/**
+	 * Return the LIMIT clause ready for inserting into a query.
+	 *
+	 * @param SQLSelect $query The expression object to build from
+	 * @param array $parameters Out parameter for the resulting query parameters
+	 * @return string The finalised limit SQL fragment
+	 */
+	public function buildLimitFragment(SQLSelect $query, array &$parameters) {
+		$nl = $this->getSeparator();
+
+		// Ensure limit is given
+		$limit = $query->getLimit();
+		if(empty($limit)) return '';
+		
+		// For literal values return this as the limit SQL
+		if( ! is_array($limit)) {
+			return "{$nl}LIMIT $limit";
+		}
+
+		// Assert that the array version provides the 'limit' key
+		if( ! array_key_exists('limit', $limit) || ($limit['limit'] !== null && ! is_numeric($limit['limit']))) {
+			throw new InvalidArgumentException(
+				'DBQueryBuilder::buildLimitSQL(): Wrong format for $limit: '. var_export($limit, true)
+			);
+		}
+
+		if($limit['limit'] === null) {
+			$limit['limit'] = 'ALL';
+		}
+		
+		$clause = "{$nl}LIMIT {$limit['limit']}";
+		if(isset($limit['start']) && is_numeric($limit['start']) && $limit['start'] !== 0) {
+			$clause .= " OFFSET {$limit['start']}";
+		}
+		return $clause;
+	}
+
+}