This pull request significantly improves PostgreSQL array type handling
and conversion in the `pgsql` driver, providing more accurate type
mapping and conversion logic, especially for array types. It introduces
comprehensive documentation, refactors conversion logic to use the `pq`
package for array types, and adds extensive unit tests to ensure
correctness and error handling. Additionally, minor enhancements and
clarifications are made to upsert formatting and table field queries.
### PostgreSQL Array Type Handling and Conversion
* Refactored `CheckLocalTypeForField` and `ConvertValueForLocal` methods
in `contrib/drivers/pgsql/pgsql_convert.go` to accurately map PostgreSQL
array types (such as `_int2`, `_int4`, `_int8`, `_float4`, `_float8`,
`_bool`, `_varchar`, `_text`, `_char`, `_bpchar`, `_numeric`,
`_decimal`, `_money`, `_bytea`) to their corresponding Go types, using
the `pq` package for conversion. Added detailed documentation and
mapping tables for supported types.
[[1]](diffhunk://#diff-a3b1e68bfa29fbcfda7c703bbe875fa82e958f6c3ad942ef82193a9dd8ad67e2R46-R63)
[[2]](diffhunk://#diff-a3b1e68bfa29fbcfda7c703bbe875fa82e958f6c3ad942ef82193a9dd8ad67e2L56-R103)
[[3]](diffhunk://#diff-a3b1e68bfa29fbcfda7c703bbe875fa82e958f6c3ad942ef82193a9dd8ad67e2R112-R209)
* Added comprehensive unit tests in
`contrib/drivers/pgsql/pgsql_z_unit_convert_test.go` to verify type
mapping and conversion for all supported array types, including error
cases for invalid input.
### Utility and API Improvements
* Added a new `Bools()` method to the `gvar.Var` type in
`container/gvar/gvar_slice.go` for converting values to `[]bool`, with
corresponding unit tests in `container/gvar/gvar_z_unit_slice_test.go`.
[[1]](diffhunk://#diff-32e887e540e0170f785508d105cb794e4d54d854b53b6950973c80022973c490R11-R15)
[[2]](diffhunk://#diff-01453eca4d4b3e35d07ca105cb924c6441d0cd9df6cbcc337a89832c8d53057fR24-R41)
### SQL Formatting and Documentation
* Improved documentation and formatting in the upsert logic of
`contrib/drivers/pgsql/pgsql_format_upsert.go` to clarify the use of
`EXCLUDED` in PostgreSQL's `ON CONFLICT DO UPDATE`.
* Enhanced readability of the table field query in
`contrib/drivers/pgsql/pgsql_table_fields.go` by reformatting SQL and
clarifying field extraction.
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Co-authored-by: hailaz <739476267@qq.com>
Co-authored-by: houseme <housemecn@gmail.com>
