updatable-views

UPDATE on seemingly key preserving view in Oracle raises ORA-01779

由 强颜欢笑 提交于 2021-02-07 06:47:58
问题 Problem I'm trying to refactor a low-performing MERGE statement to an UPDATE statement in Oracle 12.1.0.2.0. The MERGE statement looks like this: MERGE INTO t USING ( SELECT t.rowid rid, u.account_no_new FROM t, u, v WHERE t.account_no = u.account_no_old AND t.contract_id = v.contract_id AND v.tenant_id = u.tenant_id ) s ON (t.rowid = s.rid) WHEN MATCHED THEN UPDATE SET t.account_no = s.account_no_new It is mostly low performing because there are two expensive accesses to the large (100M rows

Updatable mysql views keeping null values

由 两盒软妹~` 提交于 2019-12-24 08:52:10
问题 We've table1 with columns (id, firstname, lastname, gender). Then table2 with columns (manid, bodyfat, mandate, matchid) Then table3 with columns (womanid, bodyfat, womandate, wmatchid) So, here i want to make an updatable mysql view with columns (id, firstname, lastname, gender) from table1, columns (bodyfat, mandate) from table2 and columns (bodyfat, womandate) from table3. The bodyfat is calculated through javascript and sended to database with php, so as you can understand in each row

use of views to protect the actual tables in sql

由 ￡可爱￡侵袭症＋ 提交于 2019-12-11 16:36:53
问题 how do views act as a mediator between the actual tables and an end user ? what's the internal process which occurs when a view is created. i mean that when a view is created on a table, then does it stands like a wall between the table and the end user or else? how do views protect the actual tables, only with the check option? but if a user inserts directly into the table then how come do i protect the actual tables? if he/she does not use : insert into **vw** values() , but uses: insert

Is it possible to insert data into a MySQL view?

由 两盒软妹~` 提交于 2019-11-28 03:33:53
I made a MySQL view with 4 tables. Is it possible to insert data into the view and have MySQL automatically pass the data into the right table? If you are using inner joins, and your view contains all the columns in the base tables, then your view might be updatable. However, for a multiple-table updatable view, INSERT can work if it inserts into a single table. You could split your insert operation into multiple INSERT statements. You may want to check out the following article for more information on the topic: MySQL Reference Manual :: Updatable and Insertable Views Consider the following

Is it possible to insert data into a MySQL view?

由 拜拜、爱过 提交于 2019-11-27 19:14:23
问题 I made a MySQL view with 4 tables. Is it possible to insert data into the view and have MySQL automatically pass the data into the right table? 回答1: If you are using inner joins, and your view contains all the columns in the base tables, then your view might be updatable. However, for a multiple-table updatable view, INSERT can work if it inserts into a single table. You could split your insert operation into multiple INSERT statements. You may want to check out the following article for more
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