WingsGo commented on a change in pull request #4009:
URL: https://github.com/apache/incubator-doris/pull/4009#discussion_r449728088
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File path: be/src/olap/schema_change.cpp
##########
@@ -194,6 +194,64 @@ ColumnMapping*
RowBlockChanger::get_mutable_column_mapping(size_t column_index)
break; \
}
+struct ConvertTypeMapHash {
+ size_t operator()(const std::pair<FieldType, FieldType>& pair) const {
+ return (pair.first + 31) ^ pair.second;
+ }
+};
+
+class ConvertTypeResolver {
+DECLARE_SINGLETON(ConvertTypeResolver);
+public:
+ bool get_convert_type_info(const FieldType from_type, const FieldType
to_type) const {
+ return _convert_type_set.find(std::make_pair(from_type, to_type)) !=
_convert_type_set.end();
+ }
+
+ template<FieldType from_type, FieldType to_type>
+ void add_convert_type_mapping() {
+ _convert_type_set.emplace(std::make_pair(from_type, to_type));
+ }
+
+private:
+ typedef std::pair<FieldType, FieldType> convert_type_pair;
+ std::unordered_set<convert_type_pair, ConvertTypeMapHash>
_convert_type_set;
+
+ DISALLOW_COPY_AND_ASSIGN(ConvertTypeResolver);
+};
+
+ConvertTypeResolver::ConvertTypeResolver() {
+ // supported type convert should annotate in doc:
+ //
http://doris.incubator.apache.org/master/zh-CN/sql-reference/sql-statements/Data%20Definition/ALTER%20TABLE.html#description
+ // from varchar type
+ add_convert_type_mapping<OLAP_FIELD_TYPE_VARCHAR,
OLAP_FIELD_TYPE_TINYINT>();
+ add_convert_type_mapping<OLAP_FIELD_TYPE_VARCHAR,
OLAP_FIELD_TYPE_SMALLINT>();
+ add_convert_type_mapping<OLAP_FIELD_TYPE_VARCHAR, OLAP_FIELD_TYPE_INT>();
+ add_convert_type_mapping<OLAP_FIELD_TYPE_VARCHAR,
OLAP_FIELD_TYPE_BIGINT>();
+ add_convert_type_mapping<OLAP_FIELD_TYPE_VARCHAR,
OLAP_FIELD_TYPE_LARGEINT>();
+ add_convert_type_mapping<OLAP_FIELD_TYPE_VARCHAR, OLAP_FIELD_TYPE_FLOAT>();
Review comment:
VAHRCHAR->DOUBLE is supported add I added it. VARCHAR->DATETIME maybe
supported in next PR.
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