I have this schema
CREATE TABLE public.item (
itemid integer NOT NULL,
itemcode character(100) NOT NULL,
itemname character(100) NOT NULL,
constraint PK_ITEM primary key (ItemID)
);
create unique index ak_itemcode on Item(ItemCode);
CREATE TABLE public.store (
storeid character(20) NOT NULL,
storename character(80) NOT NULL,
constraint PK_STORE primary key (StoreID)
);
CREATE TABLE public.storeitem (
storeitemid integer NOT NULL,
itemid integer NOT NULL,
storeid character(20) NOT NULL,
constraint PK_STOREITEM primary key (ItemID, StoreID),
foreign key (StoreID) references Store(StoreID),
foreign key (ItemID) references Item(ItemID)
);
create unique index ak_storeitemid on StoreItem (StoreItemID);
And here is the data on those tables
insert into Item (ItemID, ItemCode,ItemName)
Values (1,'abc','abc');
insert into Item (ItemID, ItemCode,ItemName)
Values (2,'def','def');
insert into Item (ItemID, ItemCode,ItemName)
Values (3,'ghi','ghi');
insert into Item (ItemID, ItemCode,ItemName)
Values (4,'lmno','lmno');
insert into Item (ItemID, ItemCode,ItemName)
Values (5,'xyz','xyz');
insert into Store (StoreID, StoreName)
Values ('B1','B1');
insert into StoreItem (StoreItemID, StoreID, ItemID)
Values (1,'B1',1);
insert into StoreItem (StoreItemID, StoreID, ItemID)
Values (2,'B1',2);
insert into StoreItem (StoreItemID, StoreID, ItemID)
Values (3,'B1',3);
Now I created this new table
CREATE TABLE public.szdata (
storeid character(20) NOT NULL,
itemcode character(100) NOT NULL,
textdata character(20) NOT NULL,
constraint PK_SZDATA primary key (ItemCode, StoreID)
);
I want to have the foreign key constraints set so that it will fail when you try to insert record which is not in StoreItem. For example this must fail
insert into SZData (StoreID, ItemCode, TextData)
Values ('B1', 'xyz', 'text123');
and this must pass
insert into SZData (StoreID, ItemCode, TextData)
Values ('B1', 'abc', 'text123');
How do I achieve this without complex triggers but using table constraints?
I prefer solution without triggers. SZData table is just for accepting input from external world and it is for single purpose.
Also database import export must not be impacted
I figured out having a function to execute on constraint will solve this issue.
The function is_storeitem does the validation. I believe this feature can be used for even complex validations
create or replace function is_storeitem(pItemcode nchar(40), pStoreId nchar(20)) returns boolean as $$
select exists (
select 1
from public.storeitem si, public.item i, public.store s
where si.itemid = i.itemid and i.itemcode = pItemcode and s.Storeid = pStoreId and s.storeid = si.storeid
);
$$ language sql;
create table SZData
(
StoreID NCHAR(20) not null,
ItemCode NCHAR(100) not null,
TextData NCHAR(20) not null,
constraint PK_SIDATA primary key (ItemCode, StoreID),
foreign key (StoreID) references Store(StoreID),
foreign key (ItemCode) references Item(ItemCode),
CONSTRAINT ck_szdata_itemcode CHECK (is_storeitem(Itemcode,StoreID))
);
This perfectly works with postgres 9.6 or greater.
Related
I am trying the following codes to create a keyspace and a table inside of it:
CREATE KEYSPACE IF NOT EXISTS books WITH REPLICATION = { 'class': 'SimpleStrategy',
'replication_factor': 3 };
CREATE TABLE IF NOT EXISTS books (
id UUID PRIMARY KEY,
user_id TEXT UNIQUE NOT NULL,
scale TEXT NOT NULL,
title TEXT NOT NULL,
description TEXT NOT NULL,
reward map<INT,TEXT> NOT NULL,
image_url TEXT NOT NULL,
video_url TEXT NOT NULL,
created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);
But I do get:
SyntaxException: line 2:10 no viable alternative at input 'UNIQUE'
(...NOT EXISTS books ( id [UUID] UNIQUE...)
What is the problem and how can I fix it?
I see three syntax issues. They are mainly related to CQL != SQL.
The first, is that NOT NULL is not valid at column definition time. Cassandra doesn't enforce constraints like that at all, so for this case, just get rid of all of them.
Next, Cassandra CQL does not allow default values, so this won't work:
created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
Providing the current timestamp for created_at is something that will need to be done at write-time. Fortunately, CQL has a few of built-in functions to make this easier:
INSERT INTO books (id, user_id, created_at)
VALUES (uuid(), 'userOne', toTimestamp(now()));
In this case, I've invoked the uuid() function to generate a Type-4 UUID. I've also invoked now() for the current time. However now() returns a TimeUUID (Type-1 UUID) so I've nested it inside of the toTimestamp function to convert it to a TIMESTAMP.
Finally, UNIQUE is not valid.
user_id TEXT UNIQUE NOT NULL,
It looks like you're trying to make sure that duplicate user_ids are not stored with each id. You can help to ensure uniqueness of the data in each partition by adding user_id to the end of the primary key definition as a clustering key:
CREATE TABLE IF NOT EXISTS books (
id UUID,
user_id TEXT,
...
PRIMARY KEY (id, user_id));
This PK definition will ensure that data for books will be partitioned by id, containing multiple user_id rows.
Not sure what the relationship is between books and users is, though. If one book can have many users, then this will work. If one user can have many books, then you'll want to switch the order of the keys to this:
PRIMARY KEY (user_id, id));
In summary, a working table definition for this problem looks like this:
CREATE TABLE IF NOT EXISTS books (
id UUID,
user_id TEXT,
scale TEXT,
title TEXT,
description TEXT,
reward map<INT,TEXT>,
image_url TEXT,
video_url TEXT,
created_at TIMESTAMP,
PRIMARY KEY (id, user_id));
Insert or Update on table violates Foreign Key constraint in UNO site
Here is my Player Table
CREATE TABLE public."Players"
(
id integer NOT NULL DEFAULT nextval('"Players_id_seq"'::regclass),
game_id integer NOT NULL,
user_name text COLLATE pg_catalog."default" NOT NULL,
is_host boolean NOT NULL DEFAULT false,
is_bot boolean NOT NULL,
CONSTRAINT "Players_pkey" PRIMARY KEY (id),
CONSTRAINT "Players_game_id_fkey" FOREIGN KEY (game_id)
REFERENCES public."Games" (id) MATCH SIMPLE
ON UPDATE NO ACTION
ON DELETE CASCADE,
CONSTRAINT "Players_user_name_fkey" FOREIGN KEY (user_name)
REFERENCES public."Users" (name) MATCH SIMPLE
ON UPDATE NO ACTION
ON DELETE NO ACTION
)
here is my User Table
CREATE TABLE public."Users"
(
name text COLLATE pg_catalog."default" NOT NULL,
pwd text COLLATE pg_catalog."default" NOT NULL,
CONSTRAINT "Users_pkey" PRIMARY KEY (name)
)
Is there there any way to query on a SET type(or MAP/LIST) to find does it contain a value or not?
Something like this:
CREATE TABLE test.table_name(
id text,
ckk SET<INT>,
PRIMARY KEY((id))
);
Select * FROM table_name WHERE id = 1 AND ckk CONTAINS 4;
Is there any way to reach this query with YCQL api?
And can we use a SET type in SECONDRY INDEX?
Is there any way to reach this query with YCQL api?
YCQL does not support the CONTAINS keyword yet (feel free to open an issue for this on the YugabyteDB GitHub).
One workaround can be to use MAP<INT, BOOLEAN> instead of SET<INT> and the [] operator.
For instance:
CREATE TABLE test.table_name(
id text,
ckk MAP<int, boolean>,
PRIMARY KEY((id))
);
SELECT * FROM table_name WHERE id = 'foo' AND ckk[4] = true;
And can we use a SET type in SECONDRY INDEX?
Generally, collection types cannot be part of the primary key, or an index key.
However, "frozen" collections (i.e. collections serialized into a single value internally) can actually be part of either primary key or index key.
For instance:
CREATE TABLE table2(
id TEXT,
ckk FROZEN<SET<INT>>,
PRIMARY KEY((id))
) WITH transactions = {'enabled' : true};
CREATE INDEX table2_idx on table2(ckk);
Another option is to use with compound primary key and defining ckk as clustering key:
cqlsh> CREATE TABLE ybdemo.tt(id TEXT, ckk INT, PRIMARY KEY ((id), ckk)) WITH CLUSTERING ORDER BY (ckk DESC);
cqlsh> SELECT * FROM ybdemo.tt WHERE id='foo' AND ckk=4;
I'm trying to use node-pg-migrate to handle migrations for an ExpressJS app. I can translate most of the SQL dump into pgm.func() type calls, but I can't see any method for handling actual INSERT statements for initial data in my solution's lookup tables.
It is possible using the pgm.sql catch all:
pgm.sql(`INSERT INTO users (username, password, created, forname, surname, department, reviewer, approver, active) VALUES
('rd#example.com', 'salty', '2019-12-31 11:00:00', 'Richard', 'Dyce', 'MDM', 'No', 'No', 'Yes');`)
Note the use of backtick (`) to allow breaking the SQL statement across multiple lines.
You can use raw sql if you needed.
Create a migration file with the extension .sql and write usual requests.
This article has a great example.
My example:
-- Up Migration
CREATE TABLE users
(
id BIGSERIAL NOT NULL PRIMARY KEY,
username VARCHAR(50) NOT NULL,
email VARCHAR(50) NOT NULL,
password VARCHAR(50) NOT NULL,
class_id INTEGER NOT NULL,
created_at DATE NOT NULL,
updated_at DATE NOT NULL
);
CREATE TABLE classes
(
id INTEGER NOT NULL PRIMARY KEY,
name VARCHAR(50) NOT NULL,
health INTEGER NOT NULL,
damage INTEGER NOT NULL,
attack_type VARCHAR(50) NOT NULL,
ability VARCHAR(50) NOT NULL,
created_at DATE NOT NULL,
updated_at DATE NOT NULL
);
INSERT INTO classes (id,
name,
health,
damage,
attack_type,
ability,
created_at,
updated_at)
VALUES (0,
'Thief',
100,
25,
'Archery Shot',
'Run Away',
NOW(),
NOW());
-- Down Migration
DROP TABLE users;
DROP TABLE classes;
Please look at the following example:
Insert
INSERT INTO my_keyspace.my_table (id, name, my_info) VALUES (
3464546,
'Sumit',
{ birthday : '1990-01-01', height : '6.2 feet', weight : '74 kg' }
);
Second Insert
INSERT INTO my_keyspace.my_table (id, name, my_info) VALUES (
3464546,
'Sumit',
{ birthday : '1990-01-01', height : '6.2 feet', weight : null }
);
Consider "id" as the Primary Key.
In the second insert "weight" attribute inside "my_info" UDT is set as null. Does this create a tombstone? How null inside an UDT is stored in the Cassandra database?
Yes Setting a column to NULL is the same as writing a tombstone in some cases.