I have 2 tables in Postgres ( inventory table and event table ).
In the inventory table my primary key consist of 8 strings.
Example '03163161'.
Now I have to input them in the Event table randomly with the primary key that is on the inventory table.
In what way can I do it? I've tried googling it but no one seems to have a solution on it and I'm trying to experiment on how i can random input the PK of inventory table to the event table since the data is almost 3k.
Update#1
I've tried using the code below
INSERT INTO dashboard.event(terminal_id) VALUES (SELECT terminal_id FROM dashboard.inventory)
but i get the error:
ERROR: syntax error at or near "SELECT"
LINE 1: INSERT INTO dashboard.event(terminal_id) VALUES (SELECT term...
^
SQL state: 42601
Character: 50
Don't use the keyword VALUES with a select in the insert. See this question:
Update or Insert (multiple rows and columns) from subquery in PostgreSQL
INSERT INTO dashboard.event(terminal_id)
SELECT terminal_id
FROM dashboard.inventory --should work
I think you want the 'references' keyword. For example:
https://www.postgresql.org/docs/current/ddl-constraints.html
create table inventory
(
id INTEGER NOT NULL UNIQUE,
... other fields
);
create table events
(
eid INTEGER REFERENCES inventory(id),
... other fields
);
Related
I have created an empty table with the following SQL statement. My understanding (based on this tutorial: https://www.postgresqltutorial.com/postgresql-tutorial/postgresql-serial/) was that SERIAL PRIMARY KEY will automatically provide an auto-incremented id for every new row:
CREATE TABLE "shema".my_table
(
id SERIAL PRIMARY KEY,
transaction text NOT NULL,
service_privider text NOT NULL,
customer_id text NOT NULL,
value numeric NOT NULL
)
WITH (
OIDS = FALSE
);
ALTER TABLE "shema".my_table
OWNER to admin;
Now I am querying another tables and would like to save the result of that query into my_table. The result of the query outputs following schema:
transaction
service_provider
customer_id
value
meaning the schema of my_table minus id. when I try to execute:
INSERT into my table
Select {here is the query}
Then I am getting an error that column "id" is of type integer but expression is of type text. I interpret it that the sql query is looking for id column and cannot find it. How can I insert data into my_table without explicitly stating id number but have this id auto-generated for every row?
Always mention the columns you want to INSERT:
INSERT INTO schemaname.my_table("transaction", service_privider, customer_id, value)
SELECT ?, ?, ?, ?;
If you don't, your code will break now or somewhere in the future.
By the way, transaction is a reserved word, try to use a better column name.
I'm working on a database for my school project in which I have to produce a functional database by normalizing sample tables given to us.
One table I'm having trouble with is itineraries. I produce 3 tables from the normalization which are "Destinations", "Itineraries" and "Itinerary_Destinations".
The code for Destinations is:
create table Destinations
(
DestinationID varchar(5) primary key,
Name varchar(45)
);
The code for Itineraries is:
create table Itineraries
(
ItineraryID varchar(5),
Name varchar(45)
);
The code for the last table is:
create table Itinerary_Destinations
(
DI varchar(5) primary key,
ItineraryID varchar(5) foreign key references Itineraries(ItineraryID),
Itinerary_Name varchar(45),
DestinationID varchar(5) foreign key references Destinations(DestinationID),
Destination_Name varchar(45)
);
Data has already been inserted into all 3 tables with the exception of 'Destination_Name' and 'Itinerary_Name' columns. The code I'm attempting to use is returning as error. The code is shown below.
insert into Itinerary_Destinations (Itinerary_name)
select Name from Itineraries where
Itineraries.ItineraryID = ItineraryID;
The error it returns is
Msg 515, Level 16, State 2, Line 1 Cannot insert the value NULL into
column 'DI', table 'DDDAssignment.dbo.Itinerary_Destinations'; column
does not allow nulls. INSERT fails. The statement has been terminated.
Is there a method to accomplish the task of inserting the Destination_Name and Itinerary_Name without creating new records that require primary keys?
Or should I do it manually?
If you want to modify records which already exist, then you should be using an UPDATE rather than an INSERT:
UPDATE a
SET Itinerary_name = b.Name
FROM Itinerary_Destinations a
INNER JOIN Itinerary_name b
ON a.ItineraryID = b.ItineraryID;
But, if you do have some data which is not already logically associated with the Itinerary_Destinations table, then using an insert is appropriate.
use coalesce funtion in case null it will insert blank string, as your column does not allow null value thats why you got that error in your query
insert into Itinerary_Destinations (Itinerary_name)
select coalesce(Name,' ') from Itineraries where
Itineraries.ItineraryID = ItineraryID;
I beginning to learn how to write trigger with this basic database.
I'm also making my very 1st database.
Schema
Team:
TeamID int PK (TeamID int IDENTITY(0,1) CONSTRAINT TeamID_PK PRIMARY KEY)
TeamName nvarchar(100)
History:
HistoryID int PK (HistoryID int IDENTITY(0,1) CONSTRAINT HistoryID_PK PRIMARY KEY)
TeamID int FK REF Team(TeamID)
WinCount int
LoseCount int
My trigger: when a new team is inserted, it should insert a new history row with that team id
CREATE TRIGGER after_insert_Player
ON Team
FOR INSERT
AS
BEGIN
INSERT INTO History (TeamID, WinCount, LoseCount)
SELECT DISTINCT i.TeamID
FROM Inserted i
LEFT JOIN History h ON h.TeamID = i.TeamID
AND h.WinCount = 0 AND h.LoseCount = 0
END
Executed it returns
The select list for the INSERT statement contains fewer items than the insert list. The number of SELECT values must match the number of INSERT columns.
Please help thank. I'm using SQL Server
The error text is the best guide, it is so clear ..
You try inserting one value from i.TeamID into three columns (TeamID,WinCount,LoseCount)
consider these WinCount and LoseCount while inserting.
Note: I Think the structure of History table need to revisit, you should select WinCount and LoseCount as Expressions not as actual columns.
When you specify insert columns, you say which columns you will be filling. But in your case, right after insert you select only one column (team id).
You either have to modify the insert to contain only one column, or select, to retrieve 3 fields as in insert.
If you mention the columns where values have to be inserted(Using INSERT-SELECT).
The SELECT Statement has to contain the same number of columns that have been specified to be inserted. Also, ensure they are of the same data type.(You might face some issues otherwise)
Facing some issues with the auto-increment property in postgresql
I created a table say emp
create table emp
( empid serial,
empname varcha(50),
primary key (empid)
);
I inserted one value with empid as blank:
insert into emp (empname) values ('test1');
Next insert by specifying the empid value:
insert into emp (empid,empname) values (2,'test2');
Now, the next time if I insert a value without specifying the empid value, it will give an error because it will try to insert the empid as 2:
insert into emp (empname) values ('test3');
ERROR: duplicate key value violates unique constraint "emp_pkey"
DETAIL: Key (empid)=(2) already exists.
Can someone help me with a workaround for this issue so that with or without specifying a value, the autoincrement should pick up the max(value) +1 ??
Thanks
You can't cleanly mix use of sequences and fixed IDs. Inserting values without using the sequence won't update the sequence, so you'll get collisions.
If you're doing your manual insertions in a bulk load phase or something you can:
BEGIN
LOCK TABLE the_table IN ACCESS EXCLUSIVE MODE
Do your INSERTs
SELECT setval('seq_name', 14), replacing 14 with the new sequence value. This can be a subquery against the table.
COMMIT
... but in general, it's better to just avoid mixing sequence ID generation and manually assigned IDs.
Let's say that I want to have a table that logs the date and the number of columns in some other table (or really any sort of math / string concat etc).
CREATE TABLE `log` (
`id` INTEGER NOT NULL AUTO_INCREMENT ,
`date` DATETIME NOT NULL ,
`count` INTEGER NOT NULL ,
PRIMARY KEY (`id`)
);
Is it possible to have the count column calculated for me whenever I do an insert?
e.g. do something like:
INSERT INTO log (date='foo');
and have count calculated by mysql.
Obviously I could do it myself by doing a query to get the count and inserting it, but this would be better.
Triggers are the best tool for annotating data when a table is changed by insert, update or delete.
To automatically set the date column of a new row in the log with the current date, you'd create a trigger that looked something like this:
create trigger log_date before insert on log
for each row begin
set new.date = current_date()
end;
You definitly have to declare what to insert. This should be possible by using the INSERT ... SELECT statement.
INSERT INTO log (date, count)
SELECT DATE() as date, count(id) as count
from foo;
Which should insert a new row into the log table, containing todays date and the number of rows in the foo table. (Assuming the foo table has an id column.. Use the primary key or another indexed column)
Why don't you use information_schema.TABLES?