diff --git a/lib/Adapter.js b/lib/Adapter.js
index 5ab15bd..3381415 100755
--- a/lib/Adapter.js
+++ b/lib/Adapter.js
@@ -29,6 +29,6 @@ module.exports = class Adapter {
 	 * @return {void}
 	 */
 	close() {
-		this.instance.close();
+		this.instance.end();
 	}
 };
\ No newline at end of file
diff --git a/lib/QueryParser.js b/lib/QueryParser.js
index 282eef9..9ae14ed 100644
--- a/lib/QueryParser.js
+++ b/lib/QueryParser.js
@@ -52,8 +52,9 @@ module.exports = class QueryParser {
 		let output = [];
 
 		// Return non-array matches
-		if (helpers.isNull(array)) return null;
-		if (helpers.isScalar(array) || helpers.isUndefined(array)) return output;
+		if (helpers.isNull(array)) {
+			return null;
+		}
 
 		array.forEach(item => {
 			output.push(item);
@@ -157,9 +158,9 @@ module.exports = class QueryParser {
 			// Filter explicit literals from lists of matches
 			if (whereValues.indexOf(whereMap[key]) !== -1) {
 				let value = whereMap[key];
-				let identIndex = (helpers.isArray(parts.identifiers)) ? parts.identifiers.indexOf(value) : -1;
+				let identIndex = parts.identifiers.indexOf(value);
 				let litIndex = (helpers.isArray(parts.literals)) ? parts.literals.indexOf(value) : -1;
-				let combIndex = (helpers.isArray(parts.combined)) ? parts.combined.indexOf(value) : -1;
+				let combIndex = parts.combined.indexOf(value);
 				let funcIndex = (helpers.isArray(parts.functions)) ? parts.functions.indexOf(value) : -1;
 				let inOutputArray = outputValues.indexOf(value) !== -1;
 
@@ -190,16 +191,10 @@ module.exports = class QueryParser {
 				if (combIndex !== -1 && funcIndex === -1) {
 					// Make sure to skip functions when replacing values
 					parts.combined[combIndex] = '?';
-
-					if (! inOutputArray) {
-						outputValues.push(value);
-						inOutputArray = true;
-					}
 				}
 			}
 
 			// Filter false positive identifiers
-			parts.identifiers = parts.identifiers || [];
 			parts.identifiers = parts.identifiers.filter(item => {
 				let isInCombinedMatches = parts.combined.indexOf(item) !== -1;
 				let isNotInBlackList = this.identifierBlacklist.indexOf(item.toLowerCase()) === -1;
@@ -227,7 +222,7 @@ module.exports = class QueryParser {
 					let litIndex = parts.combined.indexOf(lit);
 
 					if (litIndex !== -1) {
-						parts.combined[litIndex] = (helpers.isArray(parts.operators)) ? '?' : '= ?';
+						parts.combined[litIndex] = '?';
 						outputValues.push(lit);
 					}
 				});
diff --git a/lib/adapters/dblite.js b/lib/adapters/dblite.js
index 9a4706e..371844e 100644
--- a/lib/adapters/dblite.js
+++ b/lib/adapters/dblite.js
@@ -16,4 +16,12 @@ module.exports = class dblite extends Adapter {
 		let args = getArgs('sql:string, [params]:array, callback:function', arguments);
 		this.instance.query(args.sql, args.params, args.callback);
 	}
+
+	/**
+	 * Close the current database connection
+	 * @return {void}
+	 */
+	close() {
+		this.instance.close();
+	}
 };
\ No newline at end of file
diff --git a/test/adapters/mysql2_test.js b/test/adapters/mysql2_test.js
index e455a50..965f3c0 100644
--- a/test/adapters/mysql2_test.js
+++ b/test/adapters/mysql2_test.js
@@ -56,6 +56,6 @@ suite('Mysql2 adapter tests', () => {
 		});
 	});
 	suiteTeardown(() => {
-		connection.end();
+		qb.end();
 	});
 });
\ No newline at end of file
diff --git a/test/adapters/mysql_test.js b/test/adapters/mysql_test.js
index ff1369f..adb2811 100644
--- a/test/adapters/mysql_test.js
+++ b/test/adapters/mysql_test.js
@@ -56,6 +56,6 @@ suite('Mysql adapter tests', () => {
 		});
 	});
 	suiteTeardown(() => {
-		connection.end();
+		qb.end();
 	});
 });
\ No newline at end of file
diff --git a/test/adapters/pg_test.js b/test/adapters/pg_test.js
index e68d896..4d53d1b 100644
--- a/test/adapters/pg_test.js
+++ b/test/adapters/pg_test.js
@@ -15,7 +15,7 @@ let config = reload(configFile)[adapterName];
 // Set up the connection
 let pg = reload(adapterName);
 let connection = new pg.Client(config.conn);
-connection.connect(function(err) {
+connection.connect(err => {
 	if (err) {
 		throw new Error(err);
 	}
@@ -59,6 +59,6 @@ suite('Pg adapter tests', () => {
 		});
 	});
 	suiteTeardown(() => {
-		connection.end();
+		qb.end();
 	});
 });
\ No newline at end of file
diff --git a/test/base_test.js b/test/base_test.js
index 8530a31..fbec2c2 100644
--- a/test/base_test.js
+++ b/test/base_test.js
@@ -3,7 +3,8 @@
 let expect = require('chai').expect,
 	reload = require('require-reload')(require),
 	glob = require('glob'),
-	nodeQuery = reload('../lib/NodeQuery');
+	nodeQuery = reload('../lib/NodeQuery'),
+	Adapter = reload('../lib/Adapter');
 
 suite('Base tests', () => {
 	suite('Sanity check', () => {
@@ -32,4 +33,11 @@ suite('Base tests', () => {
 			nodeQuery.init('foo', {}, 'bar');
 		}).to.throw(Error, 'Selected driver (Foo) does not exist!');
 	});
+
+	test('Invalid adapter', () => {
+		expect(() => {
+			let a = new Adapter();
+			a.execute();
+		}).to.throw(Error, 'Correct adapter not defined for query execution');
+	});
 });
\ No newline at end of file