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
Related
I've set up the following table:
CREATE TABLE transactions (txn_id SERIAL, stock VARCHAR NOT NULL, qty INT NOT NULL, user_id INT NOT NULL);
On inserting few rows, the table looks like this:
txn_id | stock | qty | user_id
--------+--------+-----+---------
1 | APPL | 2 | 1
2 | GOOGLE | 3 | 4
3 | TSLA | 1 | 2
Now, while adding a new insert into the table,
for example - INSERT INTO transactions (stock, qty, user_id) VALUES ('APPL', 3, 1)
if 'stock' and 'user_id' match (as in the above example), i only want the quantity to be updated in the database. Such as in this case, the row 1 entity should have its 'qty' column value incremented by +3.
Is there a solution to this without using any ORM like SQLalchemy etc. ?
You want on conflict. First set up a unique constraint on the stock/user_id columns:
alter table transactions add constraint unq_transactions_stock_user_id unique (stock, user_id);
Then use this with an on conflict statement:
insert into transactions (stock, qty, user_id)
values ('APPL', 3, 1)
on conflict on constraint unq_transactions_stock_user_id do update
set qty = coalesce(transactions.qty, 0) + excluded.qty;
I have a database with this two tables :
[OldDb].[Per].[Person]
PersonId | FirstName | LastName | Code
2003 | 'Mike' | 'Jordan' | 2
2357 | 'Sara' | 'Jacobs' | 1
3481 | 'John' | 'Gates' | 5
[OldDb].[Sal].[Customer]
CustomerId | PersonId | CustomerType
830 | 2003 | 3
945 | 2357 | 2
1333 | 3481 | 2
And my new database with same tables and schema :
[NewDb].[Per].[Person]
PersonId | FirstName | LastName | Code
[NewDb].[Sal].[Customer]
CustomerId | PersonId | CustomerType
PersonId in table Person is identity and I can use this code to copy people but PersonId's will be different from old database so I can't use the second query I said below to copy data from customer table.
INSERT INTO NewDb.per.Person
(FirstName,LastName,Code)
SELECT FirstName,LastName,Code
FROM OldDb.per.Person
INSERT INTO NewDb.Sal.Customer
(PersonId,CustomerType)
SELECT PersonId,CustomerType
FROM OldDb.Sal.Customer
Now I want a query so I can copy data to new db for both tables.
Any help would be a great help.
Thank you.
Your new database is empty, if you want to keep your old PersonId, you could use SET IDENTITY_INSERT NewDb.per.Person ON
SET IDENTITY_INSERT NewDb.per.Person ON -- then you could use personId in Insert
INSERT INTO NewDb.per.Person
(PersonId, FirstName,LastName,Code)
SELECT PersonId, FirstName,LastName,Code
FROM OldDb.per.Person
SET IDENTITY_INSERT NewDb.per.Person OFF -- remember set it off after insert
-- then insert new Customer without conflict
INSERT INTO NewDb.Sal.Customer
(PersonId,CustomerType)
SELECT PersonId,CustomerType
FROM OldDb.Sal.Custome
Reference link: SET IDENTITY_INSERT
And if you want new PersonId auto increment you could do this:
----CREATE `OldPersonId` column in your NewDb.per.Person
INSERT INTO NewDb.per.Person
(OldPersonId, FirstName,LastName,Code)
SELECT PersonId, FirstName,LastName,Code
FROM OldDb.per.Person
-- You could insert you new customer Inner join by `OldPersonId` Column
INSERT INTO NewDb.Sal.Customer
(PersonId,CustomerType)
SELECT np.PersonId,CustomerType
FROM OldDb.Sal.Customer oc
INNER JOIN NewDb.per.Person np ON oc.PersonId = np.OldPersonId
-----DELETE `OldPersonId` column in NewDb.per.Person
I was wondering when it is better to choose sequence, and when it is better
to use serial.
What I want is returning last value after insert using
SELECT LASTVAL();
I read this question
PostgreSQL Autoincrement
I never use serial before.
Check out a nice answer about Sequence vs. Serial.
Sequence will just create sequence of unique numbers. It's not a datatype. It is a sequence. For example:
create sequence testing1;
select nextval('testing1'); -- 1
select nextval('testing1'); -- 2
You can use the same sequence in multiple places like this:
create sequence testing1;
create table table1(id int not null default nextval('testing1'), firstname varchar(20));
create table table2(id int not null default nextval('testing1'), firstname varchar(20));
insert into table1 (firstname) values ('tom'), ('henry');
insert into table2 (firstname) values ('tom'), ('henry');
select * from table1;
| id | firstname |
|----|-----------|
| 1 | tom |
| 2 | henry |
select * from table2;
| id | firstname |
|----|-----------|
| 3 | tom |
| 4 | henry |
Serial is a pseudo datatype. It will create a sequence object. Let's take a look at a straight-forward table (similar to the one you will see in the link).
create table test(field1 serial);
This will cause a sequence to be created along with the table. The sequence name's nomenclature is <tablename>_<fieldname>_seq. The above one is the equivalent of:
create sequence test_field1_seq;
create table test(field1 int not null default nextval('test_field1_seq'));
Also see: http://www.postgresql.org/docs/9.3/static/datatype-numeric.html
You can reuse the sequence that is auto-created by serial datatype, or you may choose to just use one serial/sequence per table.
create table table3(id serial, firstname varchar(20));
create table table4(id int not null default nextval('table3_id_seq'), firstname varchar(20));
(The risk here is that if table3 is dropped and we continue using table3's sequence, we will get an error)
create table table5(id serial, firstname varchar(20));
insert into table3 (firstname) values ('tom'), ('henry');
insert into table4 (firstname) values ('tom'), ('henry');
insert into table5 (firstname) values ('tom'), ('henry');
select * from table3;
| id | firstname |
|----|-----------|
| 1 | tom |
| 2 | henry |
select * from table4; -- this uses sequence created in table3
| id | firstname |
|----|-----------|
| 3 | tom |
| 4 | henry |
select * from table5;
| id | firstname |
|----|-----------|
| 1 | tom |
| 2 | henry |
Feel free to try out an example: http://sqlfiddle.com/#!15/074ac/1
2021 answer using identity
I was wondering when it is better to choose sequence, and when it is better to use serial.
Not an answer to the whole question (only the part quoted above), still I guess it could help further readers. You should not use sequence nor serial, you should rather prefer identity columns:
create table apps (
id integer primary key generated always as identity
);
See this detailed answer: https://stackoverflow.com/a/55300741/978690 (and also https://wiki.postgresql.org/wiki/Don%27t_Do_This#Don.27t_use_serial)
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).
I have the following:
1. A table "patients" where I store patients data.
2. A table "tests" where I store data of tests done to each patient.
Now the problem comes as I have 2 types of tests "tests_1" and "tests_2"
So for each test done to particular patient I store the type and id of the type of test:
CREATE TABLE IF NOT EXISTS patients
(
id_patient INTEGER PRIMARY KEY,
name_patient VARCHAR(30) NOT NULL,
sex_patient VARCHAR(6) NOT NULL,
date_patient DATE
);
INSERT INTO patients values
(1,'Joe', 'Male' ,'2000-01-23');
INSERT INTO patients values
(2,'Marge','Female','1950-11-25');
INSERT INTO patients values
(3,'Diana','Female','1985-08-13');
INSERT INTO patients values
(4,'Laura','Female','1984-12-29');
CREATE TABLE IF NOT EXISTS tests
(
id_test INTEGER PRIMARY KEY,
id_patient INTEGER,
type_test VARCHAR(15) NOT NULL,
id_type_test INTEGER,
date_test DATE,
FOREIGN KEY (id_patient) REFERENCES patients(id_patient)
);
INSERT INTO tests values
(1,4,'test_1',10,'2004-05-29');
INSERT INTO tests values
(2,4,'test_2',45,'2005-01-29');
INSERT INTO tests values
(3,4,'test_2',55,'2006-04-12');
CREATE TABLE IF NOT EXISTS tests_1
(
id_test_1 INTEGER PRIMARY KEY,
id_patient INTEGER,
data1 REAL,
data2 REAL,
data3 REAL,
data4 REAL,
data5 REAL,
FOREIGN KEY (id_patient) REFERENCES patients(id_patient)
);
INSERT INTO tests_1 values
(10,4,100.7,1.8,10.89,20.04,5.29);
CREATE TABLE IF NOT EXISTS tests_2
(
id_test_2 INTEGER PRIMARY KEY,
id_patient INTEGER,
data1 REAL,
data2 REAL,
data3 REAL,
FOREIGN KEY (id_patient) REFERENCES patients(id_patient)
);
INSERT INTO tests_2 values
(45,4,10.07,18.9,1.8);
INSERT INTO tests_2 values
(55,4,17.6,1.8,18.89);
Now I think this approach is redundant or not to good...
So I would like to improve queries like
select * from tests WHERE id_patient=4;
select * from tests_1 WHERE id_patient=4;
select * from tests_2 WHERE id_patient=4;
Is there a better approach?
In this example I have 1 test of type tests_1 and 2 tests of type tests_2 for patient with id=4.
Here is a fiddle
Add a table testtype (id_test,name_test) and use it an FK to the id_type_test field in the tests table. Do not create seperate tables for test_1 and test_2
It depends on the requirement
For OLTP I would do something like the following
STAFF:
ID | FORENAME | SURNAME | DATE_OF_BIRTH | JOB_TITLE | ...
-------------------------------------------------------------
1 | harry | potter | 2001-01-01 | consultant | ...
2 | ron | weasley | 2001-02-01 | pathologist | ...
PATIENT:
ID | FORENAME | SURNAME | DATE_OF_BIRTH | ...
-----------------------------------------------
1 | hermiony | granger | 2013-01-01 | ...
TEST_TYPE:
ID | CATEGORY | NAME | DESCRIPTION | ...
--------------------------------------------------------
1 | haematology | abg | arterial blood gasses | ...
REQUEST:
ID | TEST_TYPE_ID | PATIENT_ID | DATE_REQUESTED | REQUESTED_BY | ...
----------------------------------------------------------------------
1 | 1 | 1 | 2013-01-02 | 1 | ...
RESULT_TYPE:
ID | TEST_TYPE_ID | NAME | UNIT | ...
---------------------------------------
1 | 1 | co2 | kPa | ...
2 | 1 | o2 | kPa | ...
RESULT:
ID | REQUEST_ID | RESULT_TYPE_ID | DATE_RESULTED | RESULTED_BY | RESULT | ...
-------------------------------------------------------------------------------
1 | 1 | 1 | 2013-01-02 | 2 | 5 | ...
2 | 1 | 2 | 2013-01-02 | 2 | 5 | ...
A concern I have with the above is with the unit of the test result, these can sometimes (not often) change. It may be better to place the unit un the result table.
Also consider breaking these into the major test categories as my understanding is they can be quite different e.g. histopathology and xrays are not resulted in the similar ways as haematology and microbiology are.
For OLAP I would combine request and result into one table adding derived columns such as REQUEST_TO_RESULT_MINS and make a single dimension from RESULT_TYPE and TEST_TYPE etc.
You can do this in a few ways. without knowing all the different type of cases you need to deal with.
The simplest would be 5 tables
Patients (like you described it)
Tests (like you described it)
TestType (like Declan_K suggested)
TestResultCode
TestResults
TestRsultCode describe each value that is stored for each test. TestResults is a pivoted table that can store any number of test-results per test,:
Create table TestResultCode
(
idTestResultCode int
, Code varchar(10)
, Description varchar(200)
, DataType int -- 1= Real, 2 = Varchar, 3 = int, etc.
);
Create Table TestResults
(
idPatent int -- FK
, idTest int -- FK
, idTestType int -- FK
, idTestResultCode int -- FK
, ResultsI real
, ResultsV varchar(100)
, Resultsb int
, Created datetime
)
so, basically you can fit the results you wanted to add into the tables "tests_1" and "tests_2" and any other tests you can think of.
The application reading this table, can load each test and all its values. Of course the application needs to know how to deal with each case, but you can store any type of test in this structure.