Revisit the method load_table_from_json()

[chalmerlowe]

The method load_table_from_json() shows up in a number of Issues and PRs as a source of problems OR ambiguity.

Examine this code and determine whether it (and the similar methods load_table_from_*) should be refactored to remove issues and concerns and/or improve usability.

Some of the issues/PRs where load_table_from_json() or similar methods are mentioned include:

ISSUES:

Schema and Autodetect

• load_table_from_dataframe should honor default project and dataset. python-bigquery#843
• Autodetect for BQ happening automatically even with schema defined.  python-bigquery#847
• Inability to cast int to string when appending data to table using load_table_from_json python-bigquery#906
• load_table_from_json interpolates string as int python-bigquery#1228
• BigQuery seems to automatically convert STRING to BYTES if STRING > 186 bytes python-bigquery#1563
• ALLOW_FIELD_ADDITION not working #15734
• Allow load_table_from_dataframe to Ignore Extra Schema Fields python-bigquery#1812

Retries

• feat: add job_retry argument to load_table_from_uri #15738
• Remove num_retries parameter from load_table_from_*() methods #15735

Null Values

• load_table_from_dataframe does not error out when nan in a required column - Million dollar bug python-bigquery#1692
• bigquery load_table_from_dataframe from string type will show null values python-bigquery#1737

Default Value

• Default values not initialized when job loading data with the Python API #15727

Misc

• some emoji will become wrong character stored in bigquery while using load_table_from_json python-bigquery#864
• disambiguate missing policy tags from explicitly unset policy tags python-bigquery#981
• Unable to load table from dataframe with overlapping index/column name #15726
• Provide json.dumps kwargs to load_table_from_json #15725
• Client.load_table_from_dataframe() sometimes chooses invalid column type python-bigquery#1650
• Support pyarrow.large_* as column type in dataframe upload/ download #15716
• load_table_toDataframe breaks with Arrow list fields when the list is backed by a ChunkedArray. python-bigquery#1808

PRs:

googleapis/python-bigquery#280
googleapis/python-bigquery#865
googleapis/python-bigquery#868
googleapis/python-bigquery#873
googleapis/python-bigquery#1097
googleapis/python-bigquery#1526
googleapis/python-bigquery#1634
googleapis/python-bigquery#1698

[parthea]

Transferring to google-cloud-python as the code for python-bigquery will be migrated there in 1-3 weeks.

[parthea]

Transferring this issue back to python-bigquery.

[chalmerlowe]

This issue was moved from the following repo as part of the monorepo migration: googleapis/python-bigquery