如何在Oracle中不存在時創建和索引？

Question

有沒有什麼辦法可以在oracle中創建索引只有當它們不存在？

喜歡的東西

CREATE INDEX IF NOT EXISTS ord_customer_ix 
    ON orders (customer_id); 

Answer 1

添加一個索引只有當不存在：

declare 
    already_exists exception; 
    columns_indexed exception; 
    pragma exception_init(already_exists, -955); 
    pragma exception_init(columns_indexed, -1408); 
begin 
    execute immediate 'create index ord_customer_ix on orders (customer_id)'; 
    dbms_output.put_line('created'); 
exception 
    when already_exists or columns_indexed then 
    dbms_output.put_line('skipped'); 
end;