Explicitly disallow dummy data types and special Null data type to be in table...

Explicitly disallow dummy data types and special Null data type to be in table declaration [#CLICKHOUSE-4].

dbms/src/Core/ErrorCodes.cpp

@@ -372,6 +372,7 @@ namespace ErrorCodes
     extern const int TOO_MUCH_FETCHES = 367;
     extern const int BAD_CAST = 368;
     extern const int ALL_REPLICAS_ARE_STALE = 369;
+    extern const int DATA_TYPE_CANNOT_BE_USED_IN_TABLES = 370;
 
     extern const int KEEPER_EXCEPTION = 999;
     extern const int POCO_EXCEPTION = 1000;

dbms/src/DataTypes/DataTypeNull.h

@@ -26,6 +26,11 @@ public:
         return true;
     }
 
+    bool notForTables() const override
+    {
+        return true;
+    }
+
     DataTypePtr clone() const override
     {
         return std::make_shared<DataTypeNull>();

dbms/src/DataTypes/IDataType.h

@@ -43,6 +43,9 @@ public:
     /// relevant for it? True for numbers. False for Date and DateTime types.
     virtual bool behavesAsNumber() const { return false; }
 
+    /// If this data type cannot appear in table declaration - only for intermediate values of calculations.
+    virtual bool notForTables() const { return false; }
+
     virtual DataTypePtr clone() const = 0;
 
     /** Binary serialization for range of values in column - for writing to disk/network, etc.

dbms/src/DataTypes/IDataTypeDummy.h

@@ -14,35 +14,40 @@ namespace DB
 class IDataTypeDummy : public IDataType
 {
 private:
+    bool notForTables() const override
+    {
+        return true;
+    }
+
     void throwNoSerialization() const
     {
         throw Exception("Serialization is not implemented for data type " + getName(), ErrorCodes::NOT_IMPLEMENTED);
     }
 
 public:
-    void serializeBinary(const Field & field, WriteBuffer & ostr) const override                             { throwNoSerialization(); }
-    void deserializeBinary(Field & field, ReadBuffer & istr) const override                                 { throwNoSerialization(); }
-    void serializeBinary(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override         { throwNoSerialization(); }
-    void deserializeBinary(IColumn & column, ReadBuffer & istr) const override                                 { throwNoSerialization(); }
+    void serializeBinary(const Field & field, WriteBuffer & ostr) const override                       { throwNoSerialization(); }
+    void deserializeBinary(Field & field, ReadBuffer & istr) const override                            { throwNoSerialization(); }
+    void serializeBinary(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override    { throwNoSerialization(); }
+    void deserializeBinary(IColumn & column, ReadBuffer & istr) const override                         { throwNoSerialization(); }
 
     void serializeBinaryBulk(const IColumn & column, WriteBuffer & ostr,
         size_t offset, size_t limit) const override                                                    { throwNoSerialization(); }
 
     void deserializeBinaryBulk(IColumn & column, ReadBuffer & istr, size_t limit, double avg_value_size_hint) const override { throwNoSerialization(); }
 
-    void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override             { throwNoSerialization(); }
+    void serializeText(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override           { throwNoSerialization(); }
 
-    void serializeTextEscaped(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override     { throwNoSerialization(); }
+    void serializeTextEscaped(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override    { throwNoSerialization(); }
     void deserializeTextEscaped(IColumn & column, ReadBuffer & istr) const override                         { throwNoSerialization(); }
 
     void serializeTextQuoted(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override     { throwNoSerialization(); }
-    void deserializeTextQuoted(IColumn & column, ReadBuffer & istr) const override                             { throwNoSerialization(); }
+    void deserializeTextQuoted(IColumn & column, ReadBuffer & istr) const override                          { throwNoSerialization(); }
 
-    void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr, bool) const override         { throwNoSerialization(); }
+    void serializeTextJSON(const IColumn & column, size_t row_num, WriteBuffer & ostr, bool) const override { throwNoSerialization(); }
     void deserializeTextJSON(IColumn & column, ReadBuffer & istr) const override                            { throwNoSerialization(); }
 
     void serializeTextCSV(const IColumn & column, size_t row_num, WriteBuffer & ostr) const override        { throwNoSerialization(); }
-    void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override         { throwNoSerialization(); }
+    void deserializeTextCSV(IColumn & column, ReadBuffer & istr, const char delimiter) const override       { throwNoSerialization(); }
 
     ColumnPtr createColumn() const override
     {

dbms/src/Storages/StorageFactory.cpp

@@ -51,6 +51,7 @@ namespace ErrorCodes
     extern const int FUNCTION_CANNOT_HAVE_PARAMETERS;
     extern const int TYPE_MISMATCH;
     extern const int INCORRECT_NUMBER_OF_COLUMNS;
+    extern const int DATA_TYPE_CANNOT_BE_USED_IN_TABLES;
 }
 
 
@@ -224,6 +225,15 @@ static void setGraphitePatternsFromConfig(const Context & context,
 }
 
 
+/// Some types are only for intermediate values of expressions and cannot be used in tables.
+static void checkAllTypesAreAllowedInTable(const NamesAndTypesList & names_and_types)
+{
+    for (const auto & elem : names_and_types)
+        if (elem.type->notForTables())
+            throw Exception("Data type " + elem.type->getName() + " cannot be used in tables", ErrorCodes::DATA_TYPE_CANNOT_BE_USED_IN_TABLES);
+}
+
+
 StoragePtr StorageFactory::get(
     const String & name,
     const String & data_path,
@@ -239,6 +249,10 @@ StoragePtr StorageFactory::get(
     bool attach,
     bool has_force_restore_data_flag) const
 {
+    checkAllTypesAreAllowedInTable(*columns);
+    checkAllTypesAreAllowedInTable(materialized_columns);
+    checkAllTypesAreAllowedInTable(alias_columns);
+
     if (name == "Log")
     {
         return StorageLog::create(

dbms/src/Storages/StorageFactory.h

@@ -11,6 +11,7 @@ class Context;
 
 
 /** Allows you to create a table by the name of the engine.
+  * In 'columns', 'materialized_columns', etc., Nested data structures must be flattened.
   */
 class StorageFactory : public Singleton<StorageFactory>
 {