Scenario:
User has 3 choices, 1st choice, 2nd choice, 3rd choice. Every choice is saved in db with choice number and user id.
How to put a unique validation so there can't be TWO choice#2 for user#11.
Reading documentation it seems you are only able to put for one column like email.
Is this what you want ?
CREATE UNIQUE INDEX idxu_user_choice ON my_table(choice_id, user_id);
SQL Fiddle
PostgreSQL 9.6 Schema Setup:
CREATE TABLE t
("user_id" int, "choice_id" int, "comment" varchar(8))
;
CREATE UNIQUE INDEX idxu_user_choice ON t(choice_id, user_id);
INSERT INTO t
("user_id", "choice_id", "comment")
VALUES
(1, 1, 'azer'),
(1, 2, 'zsdsfsdf'),
(2, 1, 'sdghlk')
;
Query 1:
INSERT INTO t ("user_id", "choice_id", "comment")
VALUES (2, 2, 'dfgdfgh')
Results:
Query 2:
select * from t
Results:
| user_id | choice_id | comment |
|---------|-----------|----------|
| 1 | 1 | azer |
| 1 | 2 | zsdsfsdf |
| 2 | 1 | sdghlk |
| 2 | 2 | dfgdfgh |
Query 3:
INSERT INTO t ("user_id", "choice_id", "comment")
VALUES (1, 2, 'cvbkll')
Results:
ERROR: duplicate key value violates unique constraint "idxu_user_choice" Detail: Key (choice_id, user_id)=(2, 1) already exists.
Related
I have tow table on Postgres 11 like so, with some ARRAY types columns.
CREATE TABLE test (
id INT UNIQUE,
category TEXT NOT NULL,
quantitie NUMERIC,
quantities INT[],
dates INT[]
);
INSERT INTO test (id, category, quantitie, quantities, dates) VALUES (1, 'cat1', 33, ARRAY[66], ARRAY[123678]);
INSERT INTO test (id, category, quantitie, quantities, dates) VALUES (2, 'cat2', 99, ARRAY[22], ARRAY[879889]);
CREATE TABLE test2 (
idweb INT UNIQUE,
quantities INT[],
dates INT[]
);
INSERT INTO test2 (idweb, quantities, dates) VALUES (1, ARRAY[34], ARRAY[8776]);
INSERT INTO test2 (idweb, quantities, dates) VALUES (3, ARRAY[67], ARRAY[5443]);
I'm trying to update data from table test2 to table test only on rows with same id. inside ARRAY of table test and keeping originals values.
I use INSERT on conflict,
how to update only 2 columns quantities and dates.
running the sql under i've got also an error that i don't understand the origin.
Schema Error: error: column "quantitie" is of type numeric but expression is of type integer[]
INSERT INTO test (SELECT * FROM test2 WHERE idweb IN (SELECT id FROM test))
ON CONFLICT (id)
DO UPDATE
SET
quantities = array_cat(EXCLUDED.quantities, test.quantities),
dates = array_cat(EXCLUDED.dates, test.dates);
https://www.db-fiddle.com/f/rs8BpjDUCciyZVwu5efNJE/0
is there a better way to update table test from table test2, or where i'm missing the sql?
update to show result needed on table test:
**Schema (PostgreSQL v11)**
| id | quantitie | quantities | dates | category |
| --- | --------- | ---------- | ----------- | --------- |
| 2 | 99 | 22 | 879889 | cat2 |
| 1 | 33 | 34,66 | 8776,123678 | cat1 |
Basically, your query fails because the structures of the tables do not match - so you cannot insert into test select * from test2.
You could work around this by adding "fake" columns to the select list, like so:
insert into test
select idweb, 'foo', 0, quantities, dates from test2 where idweb in (select id from test)
on conflict (id)
do update set
quantities = array_cat(excluded.quantities, test.quantities),
dates = array_cat(excluded.dates, test.dates);
But this looks much more convoluted than needed. Essentially, you want an update statement, so I would just recommend:
update test
set
dates = test2.dates || test.dates,
quantities = test2.quantities || test.quantities
from test2
where test.id = test2.idweb
Note that this ues || concatenation operator instead of array_cat() - it is shorter to write.
Demo on DB Fiddle:
id | category | quantitie | quantities | dates
-: | :------- | --------: | :--------- | :------------
2 | cat2 | 99 | {22} | {879889}
1 | cat1 | 33 | {34,66} | {8776,123678}
I have a table postgres that uses the array type of data, it allows some magic making it possible to avoid having more tables, but the non-standard nature of this makes it more difficult to operate with for a beginner.
I would like to get some summary data out of it.
Sample content:
CREATE TABLE public.cts (
id serial NOT NULL,
day timestamp NULL,
ct varchar[] NULL,
CONSTRAINT ctrlcts_pkey PRIMARY KEY (id)
);
INSERT INTO public.cts
(id, day, ct)
VALUES(29, '2015-01-24 00:00:00.000', '{ct286,ct281}');
INSERT INTO public.cts
(id, day, ct)
VALUES(30, '2015-01-25 00:00:00.000', '{ct286,ct281}');
INSERT INTO public.cts
(id, day, ct)
VALUES(31, '2015-01-26 00:00:00.000', '{ct286,ct277,ct281}');
I would like to get the totals per array member occurence totalized, with an output like this for example:
name | value
ct286 | 3
ct281 | 3
ct277 | 1
Use Postgres function array unnest():
SELECT name, COUNT(*) cnt
FROM cts, unnest(ct) as u(name)
GROUP BY name
Demo on DB Fiddle:
| name | cnt |
| ----- | --- |
| ct277 | 1 |
| ct281 | 3 |
| ct286 | 3 |
I have a table like this:
id | person | supporter | referredby|
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
0 | ABC | DEF | |
1 | ABC | GHI | DEF |
2 | CBA | FED | |
3 | CBA | IHG | FED |
What I'm trying to accomplish is I'd like postgres to reject an INSERT if the value in referredby isn't in the supporter column for a specific person. (null referredby is ok)
For example, with the data above:
4, 'ABC', 'JKL', null: accepted (can be null)
4, 'ABC', 'JKL', 'IHG': rejected (IHG not listed as a supporter for ABC)
4, 'ABC', 'JKL', 'DEF': accepted (DEF is listed as a supporter for ABC)
Maybe a check constraint? I'm not sure how to piece it together
Add a foreign key that references person, supporter. (Needs to be unique key.)
alter table t add constraint cname unique(person, supporter);
alter table t add constraint fk foreign key (person, referredby)
references t (person, supporter);
(ANSI SQL syntax, but probably also supported by Postgresql.)
I was creating the database in SQLite Manager & by mistake I forgot to mention a row.
Now, I want to add a row in the middle manually & below it the rest of the Auto-increment keys should be increased by automatically by 1 . I hope my problem is clear.
Thanks.
You shouldn't care about key values, just append your row at the end.
If you really need to do so, you could probably just update the keys with something like this. If you want to insert the new row at key 87
Make room for the key
update mytable
set key = key + 1
where key >= 87
Insert your row
insert into mytable ...
And finally update the key for the new row
update mytable
set key = 87
where key = NEW_ROW_KEY
I would just update IDs, incrementing them, then insert record setting ID manually:
CREATE TABLE cats (
id INTEGER PRIMARY KEY AUTOINCREMENT,
name VARCHAR
);
INSERT INTO cats (name) VALUES ('John');
INSERT INTO cats (name) VALUES ('Mark');
SELECT * FROM cats;
| 1 | John |
| 2 | Mark |
UPDATE cats SET ID = ID + 1 WHERE ID >= 2; -- "2" is the ID of forgotten record.
SELECT * FROM cats;
| 1 | John |
| 3 | Mark |
INSERT INTO cats (id, name) VALUES (2, 'SlowCat'); -- "2" is the ID of forgotten record.
SELECT * FROM cats;
| 1 | John |
| 2 | SlowCat |
| 3 | Mark |
Next record, inserted using AUTOINCREMENT functionality, will have next-to-last ID (4 in our case).
In a database that contains many tables, I need to write a SQL script to insert data if it is not exist.
Table currency
| id | Code | lastupdate | rate |
+--------+---------+------------+-----------+
| 1 | USD | 05-11-2012 | 2 |
| 2 | EUR | 05-11-2012 | 3 |
Table client
| id | name | createdate | currencyId|
+--------+---------+------------+-----------+
| 4 | tony | 11-24-2010 | 1 |
| 5 | john | 09-14-2010 | 2 |
Table: account
| id | number | createdate | clientId |
+--------+---------+------------+-----------+
| 7 | 1234 | 12-24-2010 | 4 |
| 8 | 5648 | 12-14-2010 | 5 |
I need to insert to:
currency (id=3, Code=JPY, lastupdate=today, rate=4)
client (id=6, name=Joe, createdate=today, currencyId=Currency with Code 'USD')
account (id=9, number=0910, createdate=today, clientId=Client with name 'Joe')
Problem:
script must check if row exists or not before inserting new data
script must allow us to add a foreign key to the new row where this foreign related to a row already found in database (as currencyId in client table)
script must allow us to add the current datetime to the column in the insert statement (such as createdate in client table)
script must allow us to add a foreign key to the new row where this foreign related to a row inserted in the same script (such as clientId in account table)
Note: I tried the following SQL statement but it solved only the first problem
INSERT INTO Client (id, name, createdate, currencyId)
SELECT 6, 'Joe', '05-11-2012', 1
WHERE not exists (SELECT * FROM Client where id=6);
this query runs without any error but as you can see I wrote createdate and currencyid manually, I need to take currency id from a select statement with where clause (I tried to substitute 1 by select statement but query failed).
This is an example about what I need, in my database, I need this script to insert more than 30 rows in more than 10 tables.
any help
You wrote
I tried to substitute 1 by select statement but query failed
But I wonder why did it fail? What did you try? This should work:
INSERT INTO Client (id, name, createdate, currencyId)
SELECT
6,
'Joe',
current_date,
(select c.id from currency as c where c.code = 'USD') as currencyId
WHERE not exists (SELECT * FROM Client where id=6);
It looks like you can work out if the data exists.
Here is a quick bit of code written in SQL Server / Sybase that I think answers you basic questions:
create table currency(
id numeric(16,0) identity primary key,
code varchar(3) not null,
lastupdated datetime not null,
rate smallint
);
create table client(
id numeric(16,0) identity primary key,
createddate datetime not null,
currencyid numeric(16,0) foreign key references currency(id)
);
insert into currency (code, lastupdated, rate)
values('EUR',GETDATE(),3)
--inserts the date and last allocated identity into client
insert into client(createddate, currencyid)
values(GETDATE(), ##IDENTITY)
go