documentation (incomplete) + patch

README.MD

 # js-db
 
 Module used for communication between NodeJS and PostgreSQL
+
+## Creating DB instance
+
+To create a new DB instance call DB constructor
+
+```
+const db = new DB(params)
+```
+
+The constructor requires parameters necessary to create connection with db:
+
+| Parameter    | Description                         | Example          |
+| ------------ | ----------------------------------- | ---------------- |
+| **user**     | The user of the DB                  | lorem            |
+| **database** | The name of the DB                  | ipsum            |
+| **password** | The password of the user            | dolor.sit.amet   |
+| **host**     | The host of the DB                  | db.websupport.sk |
+| **port**     | The port to be used when connecting | 1234             |
+
+## Methods
+
+```
+db.tableExists(tableName);
+db.select(tableName, columns = '*', where = null, limit = null);
+```
+
+## Shared parameters
+
+Some parameters are shared among multiple js-db functions. These parameters are parsed by private functions (functions which names start with an underscore)
+
+### where
+
+Where can either be a String which will be concatenated to the query:
+
+```javascript
+const where = `"id" = '123' AND "lorem" = 'ipsum'"`;
+db.select('some_table_name', '*', where);
+
+// SELECT * FROM some_table_name WHERE "id" = '123' AND "lorem" = 'ipsum';
+```
+
+or a columnName : value pair
+
+```javascript
+const where = {
+  id: '123',
+  lorem: 'ipsum'
+};
+db.select('some_table_name', '*', where);
+
+// SELECT * FROM some_table_name WHERE "id" = '123' AND "lorem" = 'ipsum';
+```
+
+or a columnName : params pair
+
+```javascript
+const where = {
+  id: {
+    key: 'id',
+    operator: '>',
+    value: '123'
+  },
+  lorem: {
+    key: 'lorem',
+    operator: '=',
+    value: 'ipsum'
+  }
+};
+db.delete('some_table_name', where);
+
+// DELETE FROM some_table_name WHERE "id" > '123' AND "lorem" = 'ipsum';
+```
+
+### columns/returning
+
+Columns or returning parameter can either be an asterisk (`'*'`):
+
+```javascript
+const columns = '*';
+db.select('some_table_name', columns);
+
+// SELECT * FROM some_table_name;
+```
+
+or a String - the name of the column in case you want to select you one column:
+
+```javascript
+const columns = 'lorem';
+db.select('some_table_name', columns);
+
+// SELECT "lorem" FROM some_table_name;
+```
+
+or and Array of the columns you want to select:
+
+```javascript
+const columns = ['id', 'lorem', 'another_column'];
+db.select('some_table_name', columns);
+
+// SELECT "id", "lorem", "another_column" FROM some_table_name;
+```

index.js

@@ -78,7 +78,7 @@ class DB {
     if (typeof returning === 'string') {
       return ` RETURNING ${returning}`;
     } else if (Array.isArray(returning)) {
-      return ` RETURNING ${returning.join(',')}`;
+      return ` RETURNING ${returning.map(column => `"${column}"`).join(',')}`;
     }
 
     return '';
@@ -112,7 +112,9 @@ class DB {
     if (typeof columns === 'string') {
       q = `SELECT ${columns} FROM ${tableName}`;
     } else if (Array.isArray(columns)) {
-      q = `SELECT ${columns.join(',')} FROM ${tableName}`;
+      q = `SELECT ${columns
+        .map(column => `"${column}"`)
+        .join(',')} FROM ${tableName}`;
     } else {
       throw new TypeError(
         columns +