I would like to know how can I convert the following block of Oracle PL/SQL code into SQLite so that it can be used in an Objective C program:
SELECT CUSTOMERS_ID_SEQ.NEXTVAL
INTO V_CUSTOMER_ID
FROM DUAL;
where V_CUSTOMER_ID is CUSTOMER_ID%TYPE NOT NULL, and
CUSTOMER_ID is integer type in table.
SQLite does not have sequences.
To get an autoincrementing ID, you have to use an INTEGER PRIMARY KEY column.
CL is right.
Short answer: A column declared INTEGER PRIMARY KEY will autoincrement.
Long answer: If you declare a column of a table to be INTEGER PRIMARY KEY, then whenever you insert a NULL into that column of the table, the NULL is automatically converted into an integer which is one greater than the largest value of that column over all other rows in the table, or 1 if the table is empty. (If the largest possible integer key, 9223372036854775807, then an unused key value is chosen at random.) For example, suppose you have a table like this:
CREATE TABLE t1(
a INTEGER PRIMARY KEY,
b INTEGER
);
With this table, the statement
INSERT INTO t1 VALUES(NULL,123);
is logically equivalent to saying:
INSERT INTO t1 VALUES((SELECT max(a) FROM t1)+1,123);
There is a function named sqlite3_last_insert_rowid() which will return the integer key for the most recent insert operation.
Check the following for FAQ help on SQLite: http://sqlite.org/faq.html#q1
Related
This question already has answers here:
Insert a value from a table in another table as foreign key
(3 answers)
Closed 4 months ago.
Very new to SQL in general, working on creating 2 Tables, 1 for example representing appliances with a primary key, second representing a microwave for example with its FK referencing the primary tables PK.
I'm using SERIAL as the id for the primary table, but don't know how to update or insert into the second table using that specific generated value from the first.
I've created my tables using PSQL (Postgres15) like so:
CREATE TABLE Appliances (
id SERIAL NOT NULL,
field1 integer NOT NULL DEFAULT (0),
--
PRIMARY KEY (id),
UNIQUE(id)
);
CREATE TABLE Microwaves (
id integer NOT NULL,
field1 integer,
--
PRIMARY KEY (id),
FOREIGN KEY (id) REFERENCES Appliances(id)
);
Inserting my first row into the Appliance table:
INSERT INTO Appliances(field1) VALUES(1);
SELECT * FROM Appliances;
Yields:
And a query I found somewhere pulls the current increment of the SERIAL:
SELECT currval(pg_get_serial_sequence('Appliances', 'id'));
Yields:
I'm struggling to determine how to format the INSERT statement, have tried several variations around the below input:
INSERT INTO Microwaves VALUES(SELECT currval(pg_get_serial_sequence('Appliances', 'id'), 1));
Yields:
Appreciate feedback on solving the problem as represented, or a better way to tackle this in general.
Okay looks like I stumbled on at least one solution that works in my case as taken from https://stackoverflow.com/a/50004699/3564760
DO $$
DECLARE appliance_id integer;
BEGIN
INSERT INTO Appliances(field1) VALUES('appliance2') RETURNING id INTO appliance_id;
INSERT INTO Microwaves(id, field2) VALUES(appliance_id, 100);
END $$;
Still open to other answers if this isn't ideal.
I'm trying to implement a very basic banking system.
the goal is to have different types of transactions ( deposit, withdraw, transfer ) inside a table and refer to them as IDs inside transaction tables.
CREATE TABLE transaction_types (
id INTEGER AUTO_INCREMENT PRIMARY KEY,
name VARCHAR UNIQUE NOT NULL
)
CREATE TABLE transactions (
id INTEGER AUTO_INCREMENT PRIMARY KEY,
type_id INTEGER NOT NULL,
amount FLOAT NOT NULL
)
What I'm trying to accomplish is:
When inserting into transactions table no record can have an invalid type_id ( type_id should exist in transaction_types table )
First of all get type_id from transaction_types table and then insert inside transactions table, with one query ( if it's possible, I'm fairly new )
I'm using Node.js/Typescript and PostgreSQL, any help is appreciated a lot.
For (1): modify Transactions table definition by adding REFERENCES transaction_types(id) to the end of the type_id column definition prior to the comma.
For (2), assuming you know the name of the transaction_type, you can accomplish this by:
INSERT INTO transactions(type_id, amount)
VALUES ((SELECT id from transaction_types WHERE name = 'Withdrawal'), 999.99)
By the way, my PostgreSQL requires SERIAL instead of INTEGER AUTOINCREMENT
I have the following tables:
CREATE TABLE "User" (
id integer DEFAULT nextval('"User_id_seq"'::regclass) PRIMARY KEY,
name text NOT NULL DEFAULT ''::text,
coinflips boolean[]
);
CREATE TABLE "User_coinflips_COPY" (
"nodeId" integer,
position integer,
value boolean,
id integer DEFAULT nextval('"User_coinflips_COPY_id_seq"'::regclass) PRIMARY KEY
);
I'm no looking for the SQL statement that grabs the value entry from each row in User_coinflips and inserts it as an array into the coinflips column on User.
Any help would be appreciated!
Update
Not sure if it's important but I just realized a minor mistake in my table definitions above, I replace User_coinflips with User_coinflips_COPY since that accurately describes my schema. Just for context, before it looked like this:
CREATE TABLE "User_coinflips" (
"nodeId" integer REFERENCES "User"(id) ON DELETE CASCADE,
position integer,
value boolean NOT NULL,
CONSTRAINT "User_coinflips_pkey" PRIMARY KEY ("nodeId", position)
);
You are looking for an UPDATE, rather then insert.
Use a derived table with the aggregated values to join against in the UPDATE statement:
update "User"
set conflips = t.flips
from (
select "nodeId", array_agg(value order by position) as flips
from "User_coinflips"
group by "nodeId"
) t
where t."nodeId" = "User"."nodeId";
I'm using Informix and I want to create a table like this:
CREATE TABLE increment_table
(
id SERIAL NOT NULL,
increment_column INTEGER IDENTITY (START WITH 2000, INCREMENT BY 1),
name VARCHAR(255) NOT NULL,
PRIMARY KEY (id)
);
But when I run the statement, the result is a syntax error after the INTEGER keyword. I suppose is because Informix does not support this keyword IDENTITY.
Can you help me in some ideas of how can I create an auto increment column, with this characteristics:
The column need to increment automatically in every insert.
The column isn't primary key.
Allows me set the initial number of start and the value of increment.
Can edit the value of the column.
The table already have a serial column.
I have a table defined like this:
CREATE TABLE wp_master (
gid integer NOT NULL DEFAULT nextval('wp_master_gid_seq'::regclass),
name character varying(80),
....
type integer DEFAULT 4,
CONSTRAINT p_key PRIMARY KEY (gid),
);
I want to insert data into the table from another table so I
insert into wp_master ( name, .... type) select "NAME", ...., 1 from ."Tiri2011";
but I get the error:
ERROR: duplicate key value violates unique constraint "p_key"
DETAIL: Key (gid)=(2) already exists.
Why is postgres trying to put anything into the gid field when I have explicitly not included it in the list of columns? I assumed that gid pick up its value from the sequence.
Russell
Is is trying to insert the next value of the wp_master_gid_seq sequence. Declaring an id column as serial (auto-increment) will create a sequence which has a stored value of the last inserted id which was auto-incremented. If at anytime you inserted a gid value manually, it bypassed the sequence and the autoincrement function may become broken, because the sequence value did not get updated accordingly.
The easiest way to fix it is to change the value of the sequence to the (max gid value of your table) + 1. Just execute this once and you should be ok
select setval('wp_master_gid_seq', coalesce((select max(id)+1 from wp_master), 1), false)