Hi Trevor, The tree model will definitely exist, and actually it is easier to accept and understand in the OT domain. And what we want is that tree and table are just two different views for the same data, so in our design for the same data, you can use both tree grammar and table grammar to see it.
Best regards, --------------------------- Yuan Tian On Wed, Apr 10, 2024 at 3:56 PM Trevor Hart <[email protected]> wrote: > > > > > 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 > > > > > > >
