Can you clarify whether the old tree model exists in parallel?I can
see the table being useful when querying one device but I hope we can still use
the old model as well. Thanks Trevor Hart ---- On Sun, 07 Apr 2024 23:39:02
+1200 Yuan Tian<[email protected]> wrote ---- Hi all, As introduced in
the official documentation(
https://iotdb.apache.org/UserGuide/latest/Basic-Concept/Data-Model-and-Terminology.html),
the previous modeling method of IoTDB was a tree model, which formed a full
path of a sequence from the root node to the leaf node, and a device path from
the root node to the second-to-last layer node. The previous query syntax of
IoTDB was very similar to the standard relational SQL, centered on the
sequence, with the sequence prefix name in `from clause` and the sequence
suffix name in `select clause`. This query syntax is not very friendly to users
who are accustomed to relational SQL, and they cannot apply their previous
query experience to IoTDB. Therefore, we are designing a new schema model
called table model for IoTDB. We will provide data to users in a table view in
the same way as relational databases. Each kind of device belongs to a table,
and users can use standard SQL to query this table, which greatly reduces the
learning curve of IoTDB. The functional specs for table model can be found in
https://timechor.feishu.cn/docx/C2eodP84VoJ0kuxgbhlc1fejnsh，and our dev branch
is ty/TableModelGrammar。Syntax Definition file for Table model can be found in
iotdb-core/relational-grammar/src/main/antlr4/org/apache/iotdb/db/relational/grammar/sql/RelationalSql.g4
To support the table model, we also need to change the current tsfile format,
so we need to upgrade tsfile version from V3 to V4, the new file format for
tsfile V4 can be seen in
https://apache-iotdb.feishu.cn/docx/QNeVd7mpVoWaFxxobopcCsw6ne5 Our
development is currently at a very early stage, and we would like to invite you
to discuss the functionality of the table model. Your feedback is valuable to
us and will help us shape the development of this feature. Best regards,
-------------------------- Yuan Tian
