DB: postgresql 9.5
It returns result when seraching with field name, but it returns no result when searching with id.
somedb=# select id from users where name='abc';
id
------
123
(1 row)
somedb=# select id from users where id=123;
id
----
(0 rows)
bigquant_jupyterhub=# \d users;
Table "public.users"
Column | Type | Modifiers
---------------+-----------------------------+----------------------------------------------------
id | integer | not null default nextval('users_id_seq'::regclass)
name | character varying(1023) |
_server_id | integer |
admin | boolean |
last_activity | timestamp without time zone |
cookie_id | character varying(1023) |
state | text |
auth_state | text |
Indexes:
"users_pkey" PRIMARY KEY, btree (id)
Foreign-key constraints:
"users__server_id_fkey" FOREIGN KEY (_server_id) REFERENCES servers(id)
Referenced by:
TABLE "api_tokens" CONSTRAINT "api_tokens_user_id_fkey" FOREIGN KEY (user_id) REFERENCES users(id)
TABLE "user_group_map" CONSTRAINT "user_group_map_user_id_fkey" FOREIGN KEY (user_id) REFERENCES users(id)
Thanks for all your help.
Related
I’m using Postgres 9.5.0. I have the following table
myproject=> \d my_objects;
Table "public.my_objects"
Column | Type | Modifiers
---------------------+-----------------------------+-------------------------------------
name | character varying |
day | date |
distance | double precision |
user_id | integer |
created_at | timestamp without time zone | not null
updated_at | timestamp without time zone | not null
distance_unit_id | integer |
import_completed | boolean |
id | character varying | not null default uuid_generate_v4()
linked_my_object_time_id | character varying |
web_crawler_id | integer |
address_id | character varying |
Indexes:
"my_objects_pkey" PRIMARY KEY, btree (id)
"index_my_objects_on_user_id_and_day_and_name" UNIQUE, btree (user_id, day, name)
"index_my_objects_on_user_id" btree (user_id)
"index_my_objects_on_web_crawler_id" btree (web_crawler_id)
Foreign-key constraints:
"fk_rails_5287d445c0" FOREIGN KEY (address_id) REFERENCES addresses(id) ON DELETE CASCADE
"fk_rails_970b2325bf" FOREIGN KEY (distance_unit_id) REFERENCES distance_units(id)
"fk_rails_dda3297b57" FOREIGN KEY (linked_my_object_time_id) REFERENCES my_object_times(id) ON DELETE CASCADE
"fk_rails_ebd32625bc" FOREIGN KEY (web_crawler_id) REFERENCES web_crawlers(id)
"fk_rails_fa07601dff" FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
Right now, each my_object has an address field. What I would like is when I delete the my_object, the corresponding address entry be deleted as well. Without moving the address_id column out of the my_objects table, is it possible to set something up such that when I delete a row from the my_objects table, any corresponding address data is deleted as well? Obviously, the foreign key I have set up will not get the job done.
You can do this with a trigger:
CREATE OR REPLACE FUNCTION remove_address() RETURNS trigger
LANGUAGE plpgsql AS
$$BEGIN
DELETE FROM public.addresses WHERE id = OLD.address_id;
RETURN OLD;
END;$$;
CREATE TRIGGER remove_address
AFTER DELETE ON public.my_objects FOR EACH ROW
EXECUTE PROCEDURE remove_address()
Postgres 9.2.2, Django 1.6.5, Python 2.7.5
Column | Type | Modifiers
---------------+------------------------+------------------------------------
id | integer | not null default nextval('employee_id_seq'::regclass)
first_name | character varying(75) | not null
surname | character varying(75) | not null
mname | character varying(75) |
date_of_birth | date |
staff_id | character varying(20) |
img1 | character varying(100) |
slug | character varying(50) |
created | date | not null
modified | date | not null
ppsn | character varying(20) |
Indexes:
"employee_pkey" PRIMARY KEY, btree (id)
"employee_slug_key" UNIQUE, btree (slug)
"employee_slug_like" btree (slug varchar_pattern_ops)
Referenced by:
TABLE "employeedynamic" CONSTRAINT "employee_id_refs_id_71e22023" FOREIGN KEY (employee_id) REFERENCES employee(id) DEFERRABLE INITIAL
LY DEFERRED
TABLE "drvliclicence" CONSTRAINT "employee_id_refs_id_afc65012" FOREIGN KEY (employee_id) REFERENCES employee(id) DEFERRABLE INITIALLY
DEFERRED
TABLE "coursedetail_attendance" CONSTRAINT "employee_id_refs_id_c8466b5f" FOREIGN KEY (employee_id) REFERENCES employee(id) DEFERRABLE
INITIALLY DEFERRED
.
=# select a.name from employee a where a.id = 366;
(366,Tommy,Gibbons,"",1800-08-21,1002180,images/GibbonsT2010_1.
(1 row)
Problem: How is a.name returning these details?
I've tried looking up aliases and triggers but I cannot figure this.
Check trigger:
=# \dft
List of functions
Schema | Name | Result data type | Argument data types | Type
--------+------+------------------+---------------------+------
(0 rows)
or
=# SELECT tgname FROM pg_trigger, pg_class WHERE tgrelid=pg_class.oid and relname = 'employee';
RI_ConstraintTrigger_101722
RI_ConstraintTrigger_101723
RI_ConstraintTrigger_101732
RI_ConstraintTrigger_101733
RI_ConstraintTrigger_101737
RI_ConstraintTrigger_101738
(6 rows)
Any idea how I can find what is causing a.name to return data?
I'm using Play 2.3 and trying to generate relational database by evolution for PostgreSQL 9.4.
I have following statements in my conf/evolutions/default/1.sql script:
ALTER TABLE ONLY round
ADD CONSTRAINT round_event_id_fkey FOREIGN KEY (event_id) REFERENCES event(id);
ALTER TABLE ONLY round
ADD CONSTRAINT round_event_id UNIQUE (event_id);
Following is my event table description:
Table "public.event"
Column | Type | Modifiers
-------------------------------+-----------------------------+---------------------------------------------------- id | integer | not null default nextval('event_id_seq'::regclass) related_event_hash | character varying(45) | start_time | timestamp without time zone | end_time | timestamp without time zone | name | character varying(45) | status | character varying(45) | not null owner_id | bigint | not null venue_id | bigint | participation_hash | character varying(45) | number_of_participants | integer | number_of_backup_participants | integer | created | timestamp without time zone | not null updated | timestamp without time zone | not null Indexes:
"event_pkey" PRIMARY KEY, btree (id)
"index_event_name" btree (name)
"index_event_status" btree (status)
"index_start_time" btree (start_time) Foreign-key constraints:
"event_owner_id_fkey" FOREIGN KEY (owner_id) REFERENCES person(id)
"event_venue_id_fkey" FOREIGN KEY (venue_id) REFERENCES venue(id) Referenced by:
TABLE "anonymous_person" CONSTRAINT "anonymous_person_event_id_fkey" FOREIGN KEY (event_id) REFERENCES event(id)
TABLE "mix_game" CONSTRAINT "mix_game_event_id_fkey" FOREIGN KEY (event_id) REFERENCES event(id)
TABLE "participant" CONSTRAINT "participant_event_id_fkey" FOREIGN KEY (event_id) REFERENCES event(id)
When I start the application in a browser I get this error:
Database 'default' is in an inconsistent state!
While trying to run this SQL script, we got the following error:
ERROR: there is no unique constraint matching given keys for referenced table "round" [ERROR:0, SQLSTATE:42830]
What could be wrong? How to fix this error and add foreign key constraints?
Note that it generates database round as follows without foreign key constraints.
Table "public.round"
Column | Type | Modifiers
------------------+-----------------------+----------------------------------------------------
id | integer | not null default nextval('round_id_seq'::regclass)
round_no | integer | not null
event_id | bigint | not null
state | character varying(20) | not null
team_composition | character(12) | not null
result | character varying(20) |
description | character varying(45) |
play_time | integer | not null
shift_time | integer |
change_time | integer |
Indexes:
"round_pkey" PRIMARY KEY, btree (id)
"round_event_id" UNIQUE CONSTRAINT, btree (event_id)
Take a look at the documentation.
As you see you have to delimit the both Ups and Downs section by using
comments in your SQL script.
Also, do not edit the 1.sql file because it is updated by the evolution mechanism. Start your own evolutions at 2.sql.
I'm going through 7 Databases in 7 Weeks.
In PostgreSQL, I created a venues table that has a SERIAL venue_id column.
output of \d venues
Table "public.venues"
Column | Type | Modifiers
----------------+------------------------+-----------------------------------------------------------
venue_id | integer | not null default nextval('venues_venue_id_seq'::regclass)
name | character varying(255) |
street_address | text |
type | character(7) | default 'public'::bpchar
postal_code | character varying(9) |
country_code | character(2) |
Indexes:
"venues_pkey" PRIMARY KEY, btree (venue_id)
Check constraints:
"venues_type_check" CHECK (type = ANY (ARRAY['public'::bpchar, 'private'::bpchar]))
Foreign-key constraints:
"venues_country_code_fkey" FOREIGN KEY (country_code, postal_code) REFERENCES cities(country_code, postal_code) MATCH FULL
The next step is to create an event table that references venue_id with a foreign key.
I'm trying this:
CREATE TABLE events (
event_id SERIAL PRIMARY KEY,
title text,
starts timestamp,
ends timestamp,
FOREIGN KEY (venue_id) REFERENCES venues (venue_id));
And I get this error:
ERROR: column "venue_id" referenced in forgein key not found
What's wrong?
you need to initialize the foreign key column too. see here http://www.postgresql.org/docs/current/static/ddl-constraints.html#DDL-CONSTRAINTS-FK
source & credit from #mu is too short
I'm going through the second edition of this book, so things might have changed slightly.
To create the table, you explicitly have to declare the venues_id as a column in your table, just like the rest of your columns:
CREATE TABLE events (
event_id SERIAL PRIMARY KEY,
title text,
starts timestamp,
ends timestamp,
venue_id integer, -- this is the line you're missing!
FOREIGN KEY (venue_id)
REFERENCES venues (venue_id) MATCH FULL
);
Once you have executed that, the table is created:
7dbs=# \dt
List of relations
Schema | Name | Type | Owner
--------+-----------+-------+----------
public | cities | table | postgres
public | countries | table | postgres
public | events | table | postgres
public | venues | table | postgres
I'm trying to get this query to run faster. It seems like sorting by the quality field is what really slows it down (the table has about 5 million rows) - maybe there is an index I can use for that?
Query:
SELECT "connectr_twitterpassage"."id", "connectr_twitterpassage"."third_party_id", "connectr_twitterpassage"."third_party_created", "connectr_twitterpassage"."source", "connectr_twitterpassage"."text", "connectr_twitterpassage"."author", "connectr_twitterpassage"."raw_data", "connectr_twitterpassage"."retweet_count", "connectr_twitterpassage"."favorited_count", "connectr_twitterpassage"."lang", "connectr_twitterpassage"."location", "connectr_twitterpassage"."author_followers_count", "connectr_twitterpassage"."is_retweet", "connectr_twitterpassage"."url", "connectr_twitterpassage"."author_fk_id", "connectr_twitterpassage"."quality", "connectr_twitterpassage"."is_top_tweet", "connectr_twitterpassage"."created", "connectr_twitterpassage"."modified"
FROM "connectr_twitterpassage"
INNER JOIN "connectr_twitterpassage_words" ON ("connectr_twitterpassage"."id" = "connectr_twitterpassage_words"."twitterpassage_id")
WHERE "connectr_twitterpassage_words"."word_id" = 18974807
ORDER BY "connectr_twitterpassage"."quality"
DESC LIMIT 100
Here is the EXPLAIN ANALYZE: http://explain.depesz.com/s/7zb
And the table definitions:
\d connectr_twitterpassage
Column | Type | Modifiers
------------------------+--------------------------+----------------------------------------------------------------------
id
| integer | not null default nextval('connectr_twitterpassage_id_seq'::regclass)
third_party_id | character varying(10000) | not null
source | character varying(10000) | not null
text | character varying(10000) | not null
author | character varying(10000) | not null
raw_data | character varying(10000) | not null
created | timestamp with time zone | not null
modified | timestamp with time zone | not null
third_party_created | timestamp with time zone |
retweet_count | integer | not null
favorited_count | integer | not null
lang | character varying(10000) | not null
location | character varying(10000) | not null
author_followers_count | integer | not null
is_retweet | boolean | not null
url | character varying(10000) | not null
author_fk_id | integer |
quality | bigint |
is_top_tweet | boolean | not null
Indexes:
"connectr_passage_pkey" PRIMARY KEY, btree (id)
"connectr_twitterpassage_third_party_id_uniq" UNIQUE CONSTRAINT, btree (third_party_id)
"connectr_passage_author_followers_count" btree (author_followers_count)
"connectr_passage_favorited_count" btree (favorited_count)
"connectr_passage_retweet_count" btree (retweet_count)
"connectr_passage_source" btree (source)
"connectr_passage_source_like" btree (source varchar_pattern_ops)
"connectr_passage_third_party_id" btree (third_party_id)
"connectr_passage_third_party_id_like" btree (third_party_id varchar_pattern_ops)
"connectr_twitterpassage_author_fk_id" btree (author_fk_id)
"connectr_twitterpassage_created" btree (created)
"connectr_twitterpassage_is_top_tweet" btree (is_top_tweet)
"connectr_twitterpassage_quality" btree (quality)
"connectr_twitterpassage_third_party_created" btree (third_party_created)
"id_to_quality_sorted" btree (id, quality DESC NULLS LAST)
Foreign-key constraints:
"author_fk_id_refs_id_074720a5" FOREIGN KEY (author_fk_id) REFERENCES connectr_twitteruser(id) DEFERRABLE INITIALLY DEFERRED
Referenced by:
TABLE "connectr_passageviewevent" CONSTRAINT "passage_id_refs_id_892b36a6" FOREIGN KEY (passage_id) REFERENCES connectr_twitterpassage(id) DEFERRABLE INITIALLY DEFERRED
TABLE "connectr_connection" CONSTRAINT "twitter_from_id_refs_id_8adbab24" FOREIGN KEY (twitter_from_id) REFERENCES connectr_twitterpassage(id) DEFERRABLE INITIALLY DEFERRED
TABLE "connectr_connection" CONSTRAINT "twitter_to_id_refs_id_8adbab24" FOREIGN KEY (twitter_to_id) REFERENCES connectr_twitterpassage(id) DEFERRABLE INITIALLY DEFERRED
TABLE "connectr_twitterpassage_words" CONSTRAINT "twitterpassage_id_refs_id_720f772f" FOREIGN KEY (twitterpassage_id) REFERENCES connectr_twitterpassage(id) DEFERRABLE INITIALLY DEFERRED
connectr=# \d connectr_twitterpassage_words
Table "public.connectr_twitterpassage_words"
Column | Type | Modifiers
-------------------+---------+----------------------------------------------------------------------------
id | integer | not null default nextval('connectr_twitterpassage_words_id_seq'::regclass)
twitterpassage_id | integer | not null
word_id | integer | not null
Indexes:
"connectr_twitterpassage_words_pkey" PRIMARY KEY, btree (id)
"connectr_twitterpassage_twitterpassage_id_613c80271f09fba8_uniq" UNIQUE CONSTRAINT, btree (twitterpassage_id, word_id)
"connectr_twitterpassage_words_twitterpassage_id" btree (twitterpassage_id)
"connectr_twitterpassage_words_word_id" btree (word_id)
"word_to_twitterpassage_id" btree (word_id, twitterpassage_id)
Foreign-key constraints:
"twitterpassage_id_refs_id_720f772f" FOREIGN KEY (twitterpassage_id) REFERENCES connectr_twitterpassage(id) DEFERRABLE INITIALLY DEFERRED
"word_id_refs_id_64f49629" FOREIGN KEY (word_id) REFERENCES connectr_word(id) DEFERRABLE INITIALLY DEFERRED
connectr=# \d connectr_word
Table "public.connectr_word"
Column | Type | Modifiers
---------------------+--------------------------+------------------------------------------------------------
id | integer | not null default nextval('connectr_word_id_seq'::regclass)
word | character varying(10000) | not null
created | timestamp with time zone | not null
modified | timestamp with time zone | not null
frequency | double precision |
is_username | boolean | not null
is_hashtag | boolean | not null
cloud_eligible | boolean | not null
passage_count | integer |
avg_quality | double precision |
last_twitter_search | timestamp with time zone |
cloud_approved | boolean | not null
display_word | character varying(10000) | not null
is_trend | boolean | not null
Indexes:
"connectr_word_pkey" PRIMARY KEY, btree (id)
"connectr_word_word_uniq" UNIQUE CONSTRAINT, btree (word)
"connectr_word_avg_quality" btree (avg_quality)
"connectr_word_cloud_eligible" btree (cloud_eligible)
"connectr_word_last_twitter_search" btree (last_twitter_search)
"connectr_word_passage_count" btree (passage_count)
"connectr_word_word" btree (word)
Referenced by:
TABLE "connectr_passageviewevent" CONSTRAINT "source_word_id_refs_id_178d46eb" FOREIGN KEY (source_word_id) REFERENCES connectr_word(id) DEFERRABLE INITIALLY DEFERRED
TABLE "connectr_wordmatchrewardevent" CONSTRAINT "tapped_word_id_refs_id_c2ffb369" FOREIGN KEY (tapped_word_id) REFERENCES connectr_word(id) DEFERRABLE INITIALLY DEFERRED
TABLE "connectr_connection" CONSTRAINT "word_id_refs_id_00cccde2" FOREIGN KEY (word_id) REFERENCES connectr_word(id) DEFERRABLE INITIALLY DEFERRED
TABLE "connectr_twitterpassage_words" CONSTRAINT "word_id_refs_id_64f49629" FOREIGN KEY (word_id) REFERENCES connectr_word(id) DEFERRABLE INITIALLY DEFERRED
Looking at the explain output, the sort is taking very little of the time. It is gathering the data it needs to sort that takes the time.
You must be spending a bit of time hitting the disk. If you could get your data better cached, that should speed it up a lot using the same query.
Otherwise, your best bet may be to denormalize the data by adding the quality field to the connectr_twitterpassage_words table and having an index on (word_id, quality,...)