Fokko commented on code in PR #6131:
URL: https://github.com/apache/iceberg/pull/6131#discussion_r1018441052
##########
python/pyiceberg/table/__init__.py:
##########
@@ -90,3 +103,90 @@ def snapshot_by_name(self, name: str) -> Optional[Snapshot]:
def history(self) -> List[SnapshotLogEntry]:
"""Get the snapshot history of this table."""
return self.metadata.snapshot_log
+
+
+class TableScan:
+ _always_true: ClassVar[BooleanExpression] = AlwaysTrue()
+ table: Table
+ row_filter: BooleanExpression
+ partition_filter: BooleanExpression
+ selected_fields: tuple[str]
+ case_sensitive: bool
+ snapshot_id: Optional[int]
+ options: Properties
+
+ def __init__(
+ self,
+ *,
+ table: Table,
+ row_filter: BooleanExpression = _always_true,
+ partition_filter: BooleanExpression = _always_true,
+ selected_fields: tuple[str] = ("*",),
+ case_sensitive: bool = True,
+ snapshot_id: Optional[int] = None,
+ options: Properties = EMPTY_DICT,
+ ):
+ self.table = table
+ self.row_filter = row_filter
+ self.partition_filter = partition_filter
+ self.selected_fields = selected_fields
+ self.case_sensitive = case_sensitive
+ self.snapshot_id = snapshot_id
+ self.options = options
+
+ def update(self, **overrides):
+ """Creates a copy of this table scan with updated fields."""
+ return TableScan(**{**self.__dict__, **overrides})
+
+ def snapshot(self):
+ if self.snapshot_id:
+ return self.table.snapshot_by_id(self.snapshot_id)
+
+ return self.table.current_snapshot()
+
+ def projection(self):
+ snapshot_schema = self.table.schemas().get(self.snapshot().schema_id)
or self.table.schema()
+
+ if "*" in self.selected_fields:
+ return snapshot_schema
+
+ return snapshot_schema.select(*self.selected_fields,
case_sensitive=self.case_sensitive)
+
+ def use_snapshot(self, snapshot_id: int):
+ if self.snapshot_id:
+ raise ValueError(f"Cannot override snapshot, already set snapshot
id={self.snapshot_id}")
+ if self.table.snapshot_by_id(snapshot_id):
+ return self.update(snapshot_id=snapshot_id)
+
+ raise ValueError(f"Cannot scan unknown snapshot id={snapshot_id}")
+
+ def use_ref(self, name: str):
+ if self.snapshot_id:
+ raise ValueError(f"Cannot override ref, already set snapshot
id={self.snapshot_id}")
+ if snapshot := self.table.snapshot_by_name(name):
+ return self.update(snapshot_id=snapshot.snapshot_id)
+
+ raise ValueError(f"Cannot scan unknown ref={name}")
+
+ def select(self, *field_names: str) -> "TableScan":
+ if "*" in self.selected_fields:
+ return self.update(selected_fields=field_names)
+ return
self.update(selected_fields=tuple(set(self.selected_fields).intersection(field_names)))
Review Comment:
Small bug:
```suggestion
return
self.update(selected_fields=tuple(set(self.selected_fields).intersection(set(field_names))))
```
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