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oracle constraints datatype
(2 answers)
Closed 2 years ago.
I am making a naive ratings platform db and I want to restrict a rating to be whole numbers from 1 to 5. To clarify I do not want to round or truncate, I want it to show a constraint violation if anything except 1,2,3,4,5 is entered.
The data type I'm using is smallint for rating. If I input 2.7, say, it truncates to 2 and proceeds to add the relation instance to the table. Which I don't want. How can I add a constraint to prevent this?
This is what the CHECK keyword is for (https://www.w3schools.com/sql/sql_check.asp)
If you had a table
CREATE TABLE Reviews (
Rating smallint CHECK (Rating IN (1,2,3,4,5)
);
Related
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How do I alter the position of a column in a PostgreSQL database table?
(10 answers)
Change column order in table of postgres
(1 answer)
How to change the position of column in postgresql without dumping
(1 answer)
Closed 2 years ago.
When a new column is added to a current table, this appears in the last column. eg:
added AGE columns to Students table
SELECT * FROM Students; "would show the AGE column right at the end.
Question: is it possible to change the order of these columns when such commands are executed?
If you have an existing table, you could create a VIEW with the columns reorganized, then of course, you could also type out the columns. You could also create a new table.
This question already has answers here:
ERROR 1062 (23000): Duplicate entry '2147483647' for key 'PRIMARY'
(3 answers)
Closed 2 years ago.
yesterday I had the problem that I couldn't insert multiple values into my columns. It turned out that the problem was that my key was missing an auto_increment. I've been trying to to the same thing(inserting multiple values into columns) now on another table but for some reason it doesn't work for me. I made the same changes as I did to the other table which works now. I can't imagine what I could've missed, can anyone help me with this?
Here the table specification and error:
When you mark the PK as auto-increment you do not have to insert values to that entry anymore as it will be incremented automatically, therefore will not trigger any duplicate problems due to being different to the previous PK entries. I suggest you to add only the values of the non PK columns.
INSERT INTO tbllaptops(L_ProzTyp, L_Akku, L_MietgebuehrProTag) -> VALUES ('i56600', '8000mha', '8.5')
This question already has answers here:
How to get the identity of an inserted row?
(15 answers)
Closed 5 years ago.
Here's what I'm trying to do: I add a record to the table. This record receives its unique ID number (identity). Then I want to use this ID in my code. How can I find out which ID number has just received a newly added record in my SQL Server database table?
Add an output parameter to your insert statement and return scope_identity(). If this isn't sufficient just search my answer, it will be in here a bunch.
This question already has answers here:
Default row ordering for select query in oracle
(8 answers)
Closed 7 years ago.
Hi allWhile working on Oracle I came across a situation where I need to select the rows from a table in which the recently inserted row should be at the top of my selection.
But here in my table I am not using any Identity column. I know how to do the same when there is an Identity column present, but is there any way to do this without Identity column?
Unless you have a sequential ID or Timestamp or some other field you can ORDER BY, Oracle provides no guarantee of order and you should not rely on it.
This question already has answers here:
SQL Server, How to set auto increment after creating a table without data loss?
(7 answers)
Closed 9 years ago.
I have imported a table from one database to another, the issue is the auto increment ID has now been removed, I want to add the primary key back to the original column on my copied table and get it working again by taking the last max ID when it was working and continuing to add 1 as normal, is this possible.
Thanks P
Just Check the Table.Whether Identity is must be there..Remove the identity..So it wil start from 1
The Query
DBCC CHECKIDENT('Your Table Name', RESEED, 0)