Please help me, I have a simple case that makes me little crazy, I have a table called PRODUCTS here is the structure
create table PRODUCT (
ID_PRODUCT CHAR(5) primary key not null,
NAME_PRODUCT CHAR(30),
PRICE_PRODUCT integer
)
then the second table is TRANSACTION, here is the table structure
create table TRANSACTION (
ID_TRANSACTION CHAR(5) primary key not null,
ID_PRODUCT CHAR(30) REFERENCES PRODUCTS(ID_PRODUCT),
PRICE integer,
QUANTITY integer
)
After that I want to create a trigger that works when users fill data into the ID_PRODUCT column in the TRANSACTIONS table, it is automatically trigger will fetch/select data from the column PRICE in the PRODUCTS table according to ID_PRODUCT that has been inserted, then update the column PRICE in table TRANSACTIONS
I'm a starter in SQL Server,... I hope you want to help me in this case, because I have no idea & don't know what I have to do, thanks
Something like this will probably do what you need:
CREATE TRIGGER UpdateTransaction
ON [TRANSACTION]
INSTEAD OF INSERT
AS
BEGIN
INSERT [TRANSACTION] (ID_TRANSACTION, ID_PRODUCT, PRICE, QUANTITY)
SELECT INSERTED.ID_TRANSACTION, INSERTED.ID_PRODUCT, PRODUCT.PRICE_PRODUCT, INSERTED.QUANTITY
FROM INSERTED
JOIN PRODUCT ON INSERTED.ID_PRODUCT = PRODUCT.ID_PRODUCT
END
It'll run INSTEAD of the normal insert and join the row to be INSERTED with the PRODUCT table, allowing it to insert the right PRICE_PRODUCT. You could do something similar for UPDATE's if you need to.
On a side note, TRANSACTION is a terrible name for a table - it's a reserved word in T-SQL (notice that it gets highlighted by your editor, and this website?) - it's part of the language, so I would avoid it in object names.
Perhaps naming your tables like this might be better:
TRANSACTION -> tbl_Transactions
PRODUCT -> tbl_Products
You're having data duplication by having two columns in two tables that are connected (id and price). I suggest removing the TRANSACTION.PRICE column.
You could instead create a VIEW:
CREATE VIEW V_Transaction AS
SELECT
TRANSACTION.ID_TRANSACTION,
TRANSACTION.ID_PRODUCT,
TRANSACTION.QUANTITY * PRODUCT.PRICE_PRODUCT as PRICE,
TRANSACTION.QUANTITY
FROM
TRANSACTION
JOIN ID_PRODUCT ON TRANSACTION.ID_PRODUCT = PRODUCT.ID_PRODUCT
There is just no point (that I see) to store the price per produkt and the price per transaction
Related
I am trying to create a FUNCTION that will insert complete and relevant information into an existing table. I need the FUNCTION to check if certain entities exist in another table and, if not, inserts the data. Example code below:
CREATE FUNCTION insert_payment (customer_uuid uuid, customer_name varchar(63), payment_uuid uuid, total_amount integer
So let's say that I wanted to enter a payment into a table called Payments. I want the FUNCTION to check another existing table called Customers to see if customer_uuid and customer_name already exist within the table. If not, I would like the FUNCTION to insert the customer_uuid and customer_name information into Customers as well as enter the data from all four parameters into Payments.
This is my first question to ask on Stack Overflow so if greater clarification is needed please let me know. I am also a student and still learning how to communicate effectively when talking about coding so, again, if further clarification is needed I will try my best. Thank you!
You can make use of an insert on conflict do nothing to insert the customer and skip inserting if it already exists.
So with this table definition:
create table customer (id uuid primary key, name text);
create table payment (id uuid primary key, customer_id uuid not null references customer, amount integer);
This function would do what you want:
CREATE FUNCTION insert_payment (customer_uuid uuid, customer_name varchar(63),
payment_uuid uuid, total_amount integer)
returns void
as
$$
insert into customer (id, name)
values (customer_uuid, customer_name)
on conflict do nothing;
insert into payment (id, customer_id, amount)
values (payment_uuid, customer_uuid, total_amount);
$$
language sql;
This is just as efficient as first checking the existence (select exists (...)) before inserting, because the INSERT statement will do that check anyway.
Online demo
I can help you more after knowing your table fields name but here I'm sharing a code maybe it'll help you
//set variable
$customer_uuid= $_POST['customer_uuid'];
$customer_name= $_POST['customer_name'];
//WRITE QUERY to the check-in customers table
$duplicate_customer = $this->db->prepare( "SELECT customer_uuid,customer_name FROM customers WHERE customer_uuid = '$customer_uuid' AND customer_name='customer_name'" ); $duplicate_customer->execute();
//now check data if exist in the customer table
if($duplicate_customer->rowCount() > 0){
//write here insert query to insert data in customer table
}
I have created tables T1 with columns( id as Primary key and name) and T2 with columns( id as primary key, name, t_id as foreign key references T1(id)) . I Inserted some values from inputs from a Windows form. After querying SELECT * FROM T2; using isql, all the values in the foreign key column are null instead of duplicating values in T1(id) because of the relationship created. Is they anything I have left out or need to add? The primary key of both tables are autoincremented.
You are confusing auto-incremented keys and relationship uses.
Auto-incremented keys (or generally talking, fields) just help you when you are inserting a new record on the table of the key. But when you are inserting a new record that makes a reference to a record in another table, then you must specify that record, using the foreign key field. Or in your case, the user that is inserting the "name" in T2 must say which one record on T1 that "name" in T2 is making a reference.
Your confusion on the relationship is that you are thinking that an established relationship will enforce the use of that values automatically. But the relationship just enforce the validation of the values. So, the field t_id in T2 will not use the value of the last record of T1 automatically. But if you try to insert a value that do not exist in T1 in the field t_id, the relationship will not let you do.
So, answering your question, what you left out and need to add?
You left out the part of the code that insert the value on the t_id field of T2 table.
Let me try to explain using an example that is more common.
The most common case of this is that the application insert first the T1 record and then when the user is inserting T2, the application provide a way to the user to choose which one T1 record his T2 record is referencing.
Suppose T1 is a publishers table and T2 is a book table. User insert a publisher, and when it is inserting a book it can choose which one publisher publish that book.
Field "ID" of Customers will be AUTOINCREMENT by default in table create using Event BeforeInsert on table CUSTOMERS. LOOK AT
CREATE TRIGGER nametrigger FOR nametable
ACTIVE BEFORE INSERT POSITION 0
AS
BEGIN
IF (NEW.ID IS NULL) THEN BEGIN
NEW.ID = GEN_ID(GEN_PK_ID, 1);
END
END
Now one new record in Customers
INSERT INTO Customers (CustomerName, ContactName, Address, City, PostalCode, Country)
VALUES ('Cardinal','Tom B. Erichsen','Skagen 21','Stavanger','4006','Norway');
Then ID will be automaticaly one sequencial number from 1 up to last integer or smallint or bigint as you defined in your create table (pay attencion that ID field is not include in FIELDS and VALUES) because TRIGGER
now you can use the dataset (obj) options to link the table MATER and DETAIL see in help delphi
or in SQL you can to use PARAMS FIELDS
later insert one new record in table MASTER try...
INSERT INTO xTable2 (IDcustomersField, ..., ..., ...., ....)
VALUES ( :IDcustomersField, ..., ..., ...., ....);
xTable2 may using one field ID (Primary Key) autoincrement too. this help when DELETING or UPDATING fileds in this table
Then you can say the value to :IDcustomersField in table detail using
xQuery.PARAM( 0 ).value or xQuery.PARAMBYNAME( IDcustomersField).value (here im using Query obj as example )
you can to use example with DATASOURCE in code to say the value for IDcustomersField
can to use
Events in SQL
can to use
PROCEDURE IN SQL
DONT FORGOT
you have to create Relationship between two table ( REFERENCIAL INTEGRITY and PRIMARY KEY in mater table ) NOT NULL FOR TWO FIELDS ON TABLES
I believe that understand me about my poor explanation (i dont speak english
You need to insert the values for t_id manually, after you get the ID's value from the main table T1.
Depending on your logic in the database you also can use a trigger or a stored procedure. Give us more information about what values you expect to have in NAME field in T2 after the insert? Are they duplicates from T1 or independent from T1?
If T1.NAME=T2.NAME, you can automate the process with a trigger
CREATE OR ALTER TRIGGER TR_T1_AI0 FOR T1
ACTIVE AFTER INSERT POSITION 0
AS
BEGIN
INSERT INTO T2(NAME, T_ID)
VALUES (NEW.NAME, NEW.ID);
END
If T2.NAME's value is different from T1.NAME you can use a stored procedure with parameters both names:
CREATE ORA ALTER PROCEDURE XXXX(
P_NAME_T1 TYPE OF T1.NAME,
P_NAME_T2 TYPE OF T2.NAME)
AS
DECLARE VARIABLE L_ID TYPE OF T1.ID;
BEGIN
INSERT INTO T1(NAME)
VALUES (:p_NAME_T1)
RETURNING ID INTO:L_ID;
INSERT INTO T2(NAME, T_ID)
VALUES (:P_NAME_T2, :l_ID);
END
You can use both statements from the stored procedure directly in your program if it supports the returning syntax. If not, you need an additional query with SELECT NEXT VALUE FOR GENERATOR_FOR_T1 FROM RDB$DATABASE; and use the value returned from it in both INSERT statements.
I am building Inventory Application using PhoneGap.In that i have one module STOCK for stock management.
Stock Table Query
CREATE TABLE STOCK (
sto_id INTEGER PRIMARY KEY AUTOINCREMENT,
pro_id INTEGER FOREIGNKEY REFERENCES PRODUCT(pro_id) UNIQUE,
quantity TEXT
)
INSERT OR REPLACE Query
INSERT OR REPLACE INTO STOCK (pro_id,quantity) VALUES ("1","5");
There is not a single issue with this query its working perfectly but i want to update SUM of OLD VALUES WITH NEW ONE.
Example:
pro_id quantity
1 5
This is existing record so now when i will fire above query for new transaction which have 3 quantity then quantity should be (5 (old) + 3 (new) ) = 8.
So after updateing record it looks like.
pro_id quantity
1 8
How can i solve this any idea. or let me know if i am on wrong way.
Thanks.
Actually I am not real founder of this solution. The real hero is Daverandom with the help of him i have solve my issue.
He has suggest me to follow this solution and that is really helpful to find my solution.
Older query looks like as
INSERT OR REPLACE INTO STOCK (pro_id,quantity) VALUES ("1","5");
New Query looks like as
INSERT OR IGNORE INTO STOCK (pro_id,quantity) VALUES (1,0) ;
UPDATE STOCK SET quantity = quantity + 2 WHERE pro_id=1;
Update:
If you will not add WHERE pro_id="val" in UPDATE then it will UPDATE all rows.
So that will generate will appropriate result.
When user fire query first time then quantity will be 2 and when you fire same query second time it will 4.
So, We can change that value in each update.
Again thanks to Daverandom.
In SQLite, you can create a trigger to handle such functionality:
CREATE TRIGGER t1 BEFORE INSERT ON STOCK WHEN NEW.pro_id IN (SELECT pro_id FROM STOCK) BEGIN
UPDATE STOCK SET quantity=COALESCE(NEW.quantity, 0)+COALESCE((SELECT quantity FROM STOCK WHERE pro_id=NEW.pro_id), 0) WHERE pro_id=NEW.pro_id;
SELECT RAISE(IGNORE); -- Ignore INSERT
END;
From now on, whenever you try to insert an existing pro_id, update on quantity is done instead. Conflict clause (OR REPLACE) doesn't matter as trigger will handle it (for pro_id).
Yet another, this time without triggers, using single statement solution:
INSERT OR REPLACE STOCK(pro_id, quantity)
SELECT npro_id, COALESCE(nqty, 0)+COALESCE(quantity,0) FROM (
SELECT 123 AS npro_id, 9999 AS nqty
) LEFT JOIN STOCK ON npro_id=pro_id;
Just replace 123 with new prod_id and 9999 with new quantity.
I have 6 tables:
Staff ( StaffID, Name )
Product ( ProductID, Name )
Faq ( FaqID, Question, Answer, ProductID* )
Customer (CustomerID, Name, Email)
Ticket ( TicketID, Problem, Status, Priority, LoggedTime, CustomerID* , ProductID* )
TicketUpdate ( TicketUpdateID, Message, UpdateTime, TicketID* , StaffID* )
Question to be answered:
Given a Product ID, remove the record for that Product. When a product is removed all associated FAQ can stay in the database but should have a null reference in the ProductID field. The deletion of a product should, however, also remove any associated tickets and their updates. For completeness deleted tickets and their updates should be copied to an audit table or a set of tables that maintain historical data on products, their tickets and updates. (Hint: you will need to define a additional table or set or tables to maintain this audit information and automatically copy any deleted tickets and ticket updates when a product is deleted). Your audit table/s should record the user which requested the deletion and the timestamp for the deletion operation.
I have created additional maintain_audit table:
CREATE TABLE maintain_audit(
TicketID INTEGER NOT NULL,
TicketUpdateID INTEGER NOT NULL,
Message VARCHAR(1000),
mdate TIMESTAMP NOT NULL,
muser VARCHAR(128),
PRIMARY KEY (TicketID, TicketUpdateID)
);
Addittionally I have created 1 function and trigger:
CREATE OR REPLACE FUNCTION maintain_audit()
RETURNS TRIGGER AS $BODY$
BEGIN
INSERT INTO maintain_audit (TicketID,TicketUpdateID,Message,muser,mdate)
(SELECT Ticket.ID,TicketUpdate.ID,Message,user,now() FROM Ticket, TicketUpdate WHERE Ticket.ID=TicketUpdate.TicketID AND Ticket.ProductID = OLD.ID);
RETURN OLD;
END;
$BODY$
LANGUAGE plpgsql;
CREATE TRIGGER maintain_audit
BEFORE DELETE
ON Product
FOR EACH ROW
EXECUTE PROCEDURE maintain_audit()
DELETE FROM Product WHERE Product.ID=30;
When I run this all I get this :
ERROR: null value in column "productid" violates not-null constraint
CONTEXT: SQL statement "UPDATE ONLY "public"."faq" SET "productid" = NULL WHERE $1 OPERATOR(pg_catalog.=) "productid""
GUYS,Could you help me in sorting out this problem?
What you probably want is triggers. Not sure what RDBMS you are using, but that's where you should start. I started from zero and had triggers up and running in a somewhat similar situation within an hour.
In case you don't already know, triggers do something after a specific type of query happens on a table, such as an insert, update or delete. You can do any type of query.
Another tip I would give you is not to delete anything, since that could break data integrity. You could just add an "active" boolean field, set active to false, then filter those out in most of your system's queries. Alternatively, you could just move the associated records out to a Products_archive table that has the same structure. Easy to do with:
select * into destination from source where 1=0
Still, I would do the work you need done using triggers because they're so automatic.
create a foreign key for Ticket.product_id, and TicketUpdate.Ticket_id which has ON DELETE CASCADE. This will automatically delete all tickets and ticketupdates when you delete the product.
create an audit table for Product deleters with product_id, user and timestamp. audit tables for ticket,ticketUpdate should mirror them exactly.
create a BEFORE DELETE TRIGGER for table Ticket which copies tickets to the audit table.
Do the same for TicketUpdate
Create an AFTER DETETE Trigger on Products to capture who requested a product be deleted in the product audit table.
In table FAQ create Product_id as a foreign key with ON DELETE SET NULL
I am trying to insert missing rows into a table. One of the columns is OrderNumber (sort number), this column should be +1 of the max value of OrderNumber returned for sID in the table. Some sIDs do not appear in the SPOL table which is why there is the WHERE clause at the end of the statement. I would run this statement again but set OrderNumber to 1 for the records where sID does not currently exist in the table.
The statement below doesn't work due to the OrderNumber causing issues with the primary key which is sID + OrderNumber.
How can I get the OrderNumber to increase for each row that is inserted based on the sID column?
INSERT INTO SPOL(sID, OrderNumber, oID)
SELECT
sID, OrderNumber, oID
FROM
(SELECT
sID,
(SELECT Max(OrderNumber) + 1
FROM SPOL
WHERE sID = TMPO.sID) AS OrderNumber,
oID
FROM TMPO
WHERE NOT EXISTS (SELECT * FROM SPOL
WHERE SPOL.oID = TMPO.oID)
) AS MyData
WHERE
OrderNumber IS NOT NULL
It's much better to handle this in the database design with an identity column - you don't mention whether or not you can change the schema but hopefully you can as queries will end up a lot cleaner if you don't have to manage it yourself.
You can set the Identity property to on for your OrderNumber column in SQL Server management studio, but the script it would generate clones the table with the new specification, inserts the values you've already got with Identity_Insert on, drops the original table, and renames the temporary one to replace it - this has massive overheads depending on how many rows you've got.
The most efficient way to go about it is probably:
create an additional column with the identity property on
copy across the values
rename the original column
rename the new column to the same name as the original
remove the original OrderNumber column
Once it's done, it's done though - and looks after itself. Wouldn't you rather your insert statement simply said something like this:
INSERT INTO SPOL (sID, oID)
SELECT sID, oID,
FROM TMPO
WHERE OrderNumber IS NOT NULL
Use identity(1,1) to increment your column Order Number,this would makes your task easy..!