如何在Pl/SQl中使用批量收集和插入 [英] How do I use bulk collect and insert in Pl/SQl
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问题描述
我想从一个表中获取大约600万行,并将它们全部插入到另一个表中.
如何使用BULK COLLECT
和FORALL
?
I want to fetch around 6 millions rows from one table and insert them all into another table.
How do I do it using BULK COLLECT
and FORALL
?
推荐答案
declare
-- define array type of the new table
TYPE new_table_array_type IS TABLE OF NEW_TABLE%ROWTYPE INDEX BY BINARY_INTEGER;
-- define array object of new table
new_table_array_object new_table_array_type;
-- fetch size on bulk operation, scale the value to tweak
-- performance optimization over IO and memory usage
fetch_size NUMBER := 5000;
-- define select statment of old table
-- select desiered columns of OLD_TABLE to be filled in NEW_TABLE
CURSOR old_table_cursor IS
select * from OLD_TABLE;
BEGIN
OPEN old_table_cursor;
loop
-- bulk fetch(read) operation
FETCH old_table_cursor BULK COLLECT
INTO new_table_array_object LIMIT fetch_size;
EXIT WHEN old_table_cursor%NOTFOUND;
-- do your business logic here (if any)
-- FOR i IN 1 .. new_table_array_object.COUNT LOOP
-- new_table_array_object(i).some_column := 'HELLO PLSQL';
-- END LOOP;
-- bulk Insert operation
FORALL i IN INDICES OF new_table_array_object SAVE EXCEPTIONS
INSERT INTO NEW_TABLE VALUES new_table_array_object(i);
COMMIT;
END LOOP;
CLOSE old_table_cursor;
End;
希望这会有所帮助.
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