Support stream DataFrame interface in iotdb python client

[JackieTien97]

This pull request introduces a new streaming DataFrame interface to the IoTDB Python client, enabling users to efficiently fetch large query results in manageable chunks. The main changes add support for iterating over result sets by DataFrame, buffering data internally, and updating example scripts to demonstrate the new API.

Streaming DataFrame API:

• Added has_next_df() and next_df() methods to SessionDataSet to allow users to check for and retrieve the next chunk of results as a DataFrame.
• Implemented internal buffering in IoTDBRpcDataSet with __df_buffer, and provided methods _has_buffered_data() and next_dataframe() to manage and return DataFrames of size fetch_size. [1] [2]
• Refactored result set processing logic into _process_buffer() and _build_dataframe() to support both streaming and batch DataFrame construction.

Example and usability improvements:

• Updated session_example.py and table_model_session_example.py to demonstrate usage of the new streaming DataFrame API. [1] [2]
• Added missing type import for Optional to support new method signatures.

[Copilot]

Pull request overview

This pull request adds a streaming DataFrame interface to the IoTDB Python client, enabling efficient retrieval of large query results in configurable chunks.

Changes:

• Introduced has_next_df() and next_df() methods to SessionDataSet for iterating over query results as DataFrames
• Implemented internal buffering mechanism in IoTDBRpcDataSet with next_dataframe() method that returns chunks of exactly fetch_size rows
• Refactored result_set_to_pandas() into _process_buffer() and _build_dataframe() helper methods to support both batch and streaming DataFrame operations

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
iotdb-client/client-py/iotdb/utils/iotdb_rpc_dataset.py	Added streaming buffer (__df_buffer), implemented next_dataframe() method for chunked DataFrame retrieval, refactored DataFrame construction into reusable helper methods, added Optional type import
iotdb-client/client-py/iotdb/utils/SessionDataSet.py	Added public API methods has_next_df() and next_df() that delegate to underlying RPC dataset streaming implementation
iotdb-client/client-py/table_model_session_example.py	Demonstrated usage of new streaming API with has_next_df()/next_df() pattern
iotdb-client/client-py/session_example.py	Demonstrated usage of new streaming API with has_next_df()/next_df() pattern

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 39.28%. Comparing base (30eebf2) to head (a453860).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #17035      +/-   ##
============================================
- Coverage     39.28%   39.28%   -0.01%     
  Complexity      212      212              
============================================
  Files          5104     5104              
  Lines        341484   341490       +6     
  Branches      43520    43522       +2     
============================================
- Hits         134149   134148       -1     
- Misses       207335   207342       +7     

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud