Add simple engines: TinyLog, Log, Memory

docs/table_engines.md

@@ -1,8 +1,37 @@
 Table Engines
 =============
 
+See: [ClickHouse Documentation](https://clickhouse.yandex/reference_en.html#Table+engines)
+
 Each model must have an engine instance, used when creating the table in ClickHouse.
 
+The following engines are supported by the ORM:
+
+- TinyLog
+- Log
+- Memory
+- MergeTree / ReplicatedMergeTree
+- CollapsingMergeTree / ReplicatedCollapsingMergeTree
+- SummingMergeTree / ReplicatedSummingMergeTree
+- ReplacingMergeTree / ReplicatedReplacingMergeTree
+- Buffer
+
+
+Simple Engines
+--------------
+
+`TinyLog`, `Log` and `Memory` engines do not require any parameters:
+
+    engine = engines.TinyLog()
+
+    engine = engines.Log()
+    
+    engine = engines.Memory()
+
+
+Engines in the MergeTree Family
+-------------------------------
+
 To define a `MergeTree` engine, supply the date column name and the names (or expressions) for the key columns:
 
     engine = engines.MergeTree('EventDate', ('CounterID', 'EventDate'))
@@ -24,32 +53,7 @@ For a `ReplacingMergeTree` you can optionally specify the version column:
 
     engine = engines.ReplacingMergeTree('EventDate', ('OrderID', 'EventDate', 'BannerID'), ver_col='Version')
 
-A `Buffer` engine is available for BufferModels. (See below how to use BufferModel). You can specify following parameters:
-
-    engine = engines.Buffer(Person) # you need to initialize engine with main Model. Other default parameters will be used
-    # or:
-    engine = engines.Buffer(Person, num_layers=16, min_time=10, 
-                            max_time=100, min_rows=10000, max_rows=1000000, 
-                            min_bytes=10000000, max_bytes=100000000)
-
-Buffer Models
--------------
-
-Here's how you can define Model for Buffer Engine. The Buffer Model should be inherited from models.BufferModel and main Model:
-
-    class PersonBuffer(models.BufferModel, Person):
-
-        engine = engines.Buffer(Person)
-
-Then you can insert objects into Buffer model and they will be handled by ClickHouse properly:
-
-    db.create_table(PersonBuffer)
-    suzy = PersonBuffer(first_name='Suzy', last_name='Jones')
-    dan = PersonBuffer(first_name='Dan', last_name='Schwartz')
-    db.insert([dan, suzy])
-
-Data Replication
-----------------
+### Data Replication
 
 Any of the above engines can be converted to a replicated engine (e.g. `ReplicatedMergeTree`) by adding two parameters, `replica_table_path` and `replica_name`:
 
@@ -58,6 +62,31 @@ Any of the above engines can be converted to a replicated engine (e.g. `Replicat
                                replica_name='{replica}')
 
 
+Buffer Engine
+-------------
+
+A `Buffer` engine is only used in conjunction with a `BufferModel`.
+The model should be a subclass of both `models.BufferModel` and the main model. 
+The main model is also passed to the engine:
+
+    class PersonBuffer(models.BufferModel, Person):
+
+        engine = engines.Buffer(Person)
+
+Additional buffer parameters can optionally be specified:
+
+        engine = engines.Buffer(Person, num_layers=16, min_time=10, 
+                                max_time=100, min_rows=10000, max_rows=1000000, 
+                                min_bytes=10000000, max_bytes=100000000)
+
+Then you can insert objects into Buffer model and they will be handled by ClickHouse properly:
+
+    db.create_table(PersonBuffer)
+    suzy = PersonBuffer(first_name='Suzy', last_name='Jones')
+    dan = PersonBuffer(first_name='Dan', last_name='Schwartz')
+    db.insert([dan, suzy])
+
+
 ---
 
 [<< Field Types](field_types.md) | [Table of Contents](toc.md) | [Schema Migrations >>](schema_migrations.md)

src/infi/clickhouse_orm/engines.py

@@ -5,6 +5,24 @@ class Engine(object):
         raise NotImplementedError()
 
 
+class TinyLog(Engine):
+
+    def create_table_sql(self):
+        return 'TinyLog'
+
+
+class Log(Engine):
+
+    def create_table_sql(self):
+        return 'Log'
+
+
+class Memory(Engine):
+
+    def create_table_sql(self):
+        return 'Memory'
+
+
 class MergeTree(Engine):
 
     def __init__(self, date_col, key_cols, sampling_expr=None,

tests/test_engines.py

@@ -53,6 +53,21 @@ class EnginesTestCase(unittest.TestCase):
             engine = ReplacingMergeTree('date', ('date', 'event_id', 'event_group'), 'event_uversion')
         self._create_and_insert(TestModel)
 
+    def test_tiny_log(self):
+        class TestModel(SampleModel):
+            engine = TinyLog()
+        self._create_and_insert(TestModel)
+
+    def test_log(self):
+        class TestModel(SampleModel):
+            engine = Log()
+        self._create_and_insert(TestModel)
+
+    def test_memory(self):
+        class TestModel(SampleModel):
+            engine = Memory()
+        self._create_and_insert(TestModel)
+
 
 class SampleModel(Model):