Add iterator support for DbObject with collection content #314
Description
Allowing the usage of DbObject directly in example for-loops, map() or set()-constructor without aslist() to list conversion would simplify usage of from queries returned collections.
Example implementation:
class DbObject:
...
def __iter__(self):
"""
Return generator iterating over each of the collection’s elements in
index order.
"""
self._ensure_is_collection()
ix = self._impl.get_first_index()
while ix is not None:
yield(self._impl.get_element_by_index(ix))
ix = self._impl.get_next_index(ix)Example usage with PL/SQL:
...
conn = oracledb.connect(...)
out_type = con.gettype("SYS.DBMS_SQL.VARCHAR2_TABLE")
cur = con.cursor()
out_var = cur.var(out_type, 10)
cur.execute("""
DECLARE
tbl SYS.DBMS_SQL.VARCHAR2_TABLE;
BEGIN
tbl(0) := 'red';
tbl(1) := 'blue';
tbl(2) := 'green';
:out := tbl;
END;""", out=out_var )
colors = set(out_var.getvalue())
print(colors)
cur.close()Example with SELECT:
Prepare DB:
CREATE OR REPLACE TYPE STR_TABLE_T AS TABLE OF VARCHAR2(4000);Python source:
...
cur.execute("SELECT STR_TABLE_T('first', 'second', 'third') FROM dual")
row = cur.fetchone()
for res in row[0]:
print(res)
...With table data a use case could be:
SELECT name, CAST(COLLECT(value) AS STR_TABLE_T) AS entries
FROM name_value_tab
GROUP BY name