I'm trying to create a VIEW in my database, and it shows me
"Incorrent syntax error"
Am I doing something wrong?
You selected two select statements. You should run only statement starting from Create View till where clause.
create view view_name as select id from tab where id = some_id;
Just run one statement of create view that's it.
Include GO between your Create View and Select query (or) view should be the only statement.
CREATE VIEW [dbo].[View_name] As
-- view logic
GO
Select * from table
Related
I am creating a trigger in SQL to sum up all the values in a column after a change is made. I am stuck and encountering an error when I try this:
`
CREATE OR REPLACE TRIGGER GET_NUM_ATHLETES
AFTER DELETE OR UPDATE OF NUM_ATHLETES OR INSERT ON DELEGATION
BEGIN
SELECT
SUM("A1"."NUM_") "SUM(NUM_)"
INTO x_1 FROM
"DBF19"."DELEGATION" "A1";
END;
`
My table looks like this:
ID
Num_
ABC
2
XYZ
4
I just used the Oracle SQL Developer GUI to create, but obviously doing something wrong.
You could use a view instead of maintaining the data in a table. That way the view would get the results "live" each time.
And also you wouldn't need to do the extra task of loading data into another table
CREATE VIEW NUM_ATHLETES
AS
SELECT SUM("A1"."NUM_") "SUM(NUM_)"
FROM "DBF19"."DELEGATION" "A1";
Do not create a table, use a VIEW (or if you were doing more complicated calculations a MATERIALIZED VIEW):
DROP TABLE num_athletes;
then:
CREATE VIEW num_athletes (id, num) AS
SELECT id, SUM(num_)
FROM DBF19.DELEGATION
GROUP BY id;
I am using sqlite3.
Suppose I have a view view_intermediate. I would like to create a temporary table from this view. In other words, turn the result of the view into a temporary table.
How should the SQL statement look like to do this?
SQLite supports CREATE TABLE AS..SELECT, so assuming you want the data in the table:
CREATE TABLE myTable AS
SELECT *
FROM view_intermediate;
If you want a table to be created from the view, but don't want the data, you can add a false condition.
CREATE TABLE myTable AS
SELECT *
FROM view_intermediate
WHERE 1=2;
I would like to update a view in HSQL without writing the same statement again and again.
I have a table CONTACTS with ID, First_NAME and LAST_NAME. I also have a VIEW for this table, which I created with
CREATE VIEW IDGREATERTHREE AS SELECT * FROM CONTACTS WHERE ID > 3;
How can I update my VIEW after I added a new column to my table. I want to update my table without anything like this:
ALTER VIEW IDGREATERTHREE AS SELECT * FROM CONTACTS WHERE ID > 3;
I would like to find a way to refresh my invalid view in a similar way like in Oracle:
ALTER VIEW IDGREATERTHREE COMPILE;
I am also looking for a way to select just the invalid views. WithSELECT * FROM INFORMATION_SCHEMA.VIEWS I am not able to see any difference between an invalid and a non-invalid view.
A solution for this would be to write an ON DDL trigger.
In this ON DDL trigger , you check if your modifying your table.
If this is the case, then you use Dynamic SQL to recreate your view. This is doable with plsql (you tagged with oracle). There is ample documentation on creating triggers and dynamic SQL on the Internet.
HSQLDB cannot have invalid views. When you create a view, the SELECT * FROM CONTACTS is expanded to the actual column names. When you add a column to the table the view is recompiled with the original column names and the new column is not included.
I have a table 'Goods' with different information about goods (name, price, etc). I need to create a view at the same scheme as table 'Goods' has. But the view must be empty. And when user adds new good to the view it is saved in table 'Goods', but the view remains empty when user opens it next time. So main idea is not to show existing data to the user which has access to the view.
Assuming your on a database system that supports a concept like SQL Server's CHECK OPTION, and you're allowed to create a view that doesn't have that option set, you should be fine:
create table T (ID int not null)
go
create view V
as
select * from T where 1=0
go
select * from V
go
insert into V(ID) values (10)
go
select * from V
go
select * from T
The two selects from V return 0 rows. The select from T returns one row:
ID
----
10
CHECK OPTION:
Forces all data modification statements executed against the view to follow the criteria set within select_statement. When a row is modified through a view, the WITH CHECK OPTION makes sure the data remains visible through the view after the modification is committed.
And you want the opposite - you want to allow data modifications performed through the view to create rows which are invisible through the view.
Create table Goods1 with "insert trigger" on it which make insert into Goods and delete from Goods1
As far as I know this isn't possible. The whole point of a view is that it is a view to a table or grouping of tables, ie. it must show the data that matches the view.
http://www.w3schools.com/sql/sql_view.asp
What you could do is create another table called GoodsView and add a trigger to it to INSERT into Goods table and DELETE from GoodsView afterwards.
http://publib.boulder.ibm.com/infocenter/iseries/v5r3/index.jsp?topic=%2Fsqlp%2Frbafysqltrig.htm
We've got a view that's defined like this
CREATE VIEW aView as
SELECT * from aTable Where <bunch of conditions>;
The "value" of the view is in the where-condition, so it is okay to use a Select * in this case.
When a new column is added to the underlying table, we have to redefine the view with a
CREATE OR REPLACE FORCE VIEW aView as
SELECT * from aTable Where <bunch of conditions>;
as the Select * seems to get "translated" into all the columns present at the time the view is (re-)defined.
My question: How can we avoid this extra step?
(If the answer is dependent on the RDBMS, we're using Oracle.)
I know you specified Oracle, but the behavior is the same in SQL Server.
One way to update the view with the new column is to use:
exec sp_refreshview MyViewName
go
Of course, I also agree with the other comments about not using a SELECT * in a view definition.
This extra step is mandatory in Oracle: you will have to recompile your view manually.
As you have noticed, the "*" is lost once you create a view:
SQL> create table t (id number);
Table created
SQL> create view v as select * from t;
View created
SQL> select text from user_views where view_name = 'V';
TEXT
-------------------------------------------------------
select "ID" from t
You should not be using * in your views. Specify the columns explicitly.
That way you are only retrieving the data you need, and thus avoid potential issues down the road where someone adds a column to a table that you do not want that view to return (e.g., a large binary column that would adversely impact performance).
Yes, you need to recompile the view to add another column, but this is the correct process. That way you avoid other compilation issues, such as if the view reference two tables, and someone adds a duplicate column name in one of the tables. The compiler would then have issues determining which of the columns was being referred to if you did not prefix a reference to the column with a table alias, or it might complain if there are duplicate column names in the results.
The problem with automatically updating views to add columns comes when you extend your model, for example to
SELECT a.*, std_name_format(a.first_name, a.middle_names, a.last_name) long_name
or even
SELECT a.*, b.* from table_a a join table_b b....
If you have a view of just SELECT * FROM table, then you probably should be using a synonym or addressing the table directly.
If the view is hiding rows (SELECT * FROM table WHERE...), then you can look at the feature variously known as Fine Grained Access Control (FGAC), Row Level Security (RLS) or Virtual Private Database (VPD).
You might be able to do something with a DDL trigger but that would get complicated.