I have a question about creating a primary key for a table using two of its data elements along with an automatically incrementing value.
I have a table that contains
Dataset-a three letter acronym and
DepositDate
I would like to create a primary key for this table that combines dataset and depositDate with an automatically incrementing value.
I can create this column with a value that keeps growing larger, but what I would like is for it to reset with each new day.
For example, on 11/8/2013 for ACA, the first insert for the day would have an identifier of:
ACA-110813-01
the second:
ACA-110813-02
and so on
Then the first insert on 11/9/2013 would be:
ACA0-110913-01
Is this possible in table creation or through any stored procedures or triggers?
I am using SQLServer 2008
Thank you in advance.
A solution I found was to use a stored procedure to insert the data into my table.
I created a column in my target table (ledgers.deposits) called depositNum which is the value I will be incrementing.
CREATE TABLE [Ledgers].[Deposits]
(
[Dataset] [nvarchar](3),
[DepositDate] [date],
[Payer] [nvarchar](100),
[CheckNum] [nvarchar](100),
[CheckAmt] [decimal](18, 2),
[depositNum] [bigint],
[depositId] AS ((((((CONVERT([nvarchar],[Dataset],0)+'-')+ CONVERT([nvarchar],datepart(month,[DepositDate]),0))+CONVERT([nvarchar],datepart(day,[DepositDate]),0))+CONVERT([nvarchar],datepart(year,[DepositDate]),0))+'-')+CONVERT([nvarchar],[depositNum],0))))
I insert data with a stored procedure which will increment the depositNum based on the dataset and the day. Then that value is concatenated into the depositId column which I set as the primary key.
Here is the stored procedure that inserts the data and increments the depositNum.
CREATE PROCEDURE [Ledgers].[insertDeposit]
#dataset nvarchar(3),
#depositDate date,
#payer nvarchar(100),
#checkNum nvarchar(100),
#depositAmt decimal(18,2)
AS
insert into Ledgers.Deposits
values(
#dataset,
#depositDate,
#payer,
#checkNum,
#depositAmt,
(
select ISNULL(max(depositNum+1), 1)
from Ledgers.Deposits
where Dataset=#dataset and DepositDate=#depositDate
))
Hopefully that makes sense.
Related
I have a table with id column as a number which have meanings. Different types of accounts start from different ranges. E.g Organisation 10000 <-> 100000, users 1000000 <-> 1kk. How can i properly increment ids on insert (with possible concurrency problem)?
If you were doing this in Oracle's table server, you would use different SEQUENCE objects for each type of account.
The MariaDB fork of MySQL has a similar kind of SEQUENCE object, as does PostgreSQL. So if you were using MariaDB you would do something like this.
CREATE SEQUENCE IF NOT EXISTS org_account_id MINVALUE=10000 MAXVALUE=999999;
CREATE SEQUENCE IF NOT EXISTS user_account_id MINVALUE=1000000;
Then to use a sequence in place of autoincrement you'll do something like this.
INSERT INTO tbl (id, col1, col2)
VALUES (NEXTVAL(user_account_id), something, something);
In MySQL you can emulate sequence objects with dummy tables containing autoincrement ids. It's a kludge. Create the following table (one for each sequence).
CREATE TABLE user_account_id (
sequence_id BIGINT NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`sequence_id`)
);
ALTER TABLE user_account_id AUTO_INCREMENT=1000000;
Then issue these queries one after the other to insert a row with a unique user id.
INSERT INTO user_account_id () VALUES ();
DELETE FROM sequence WHERE sequence_id < LAST_INSERT_ID();
SET #id:=LAST_INSERT_ID();
INSERT INTO tbl (id, col1, col2)
VALUES (#id, something, something);
After your insert into the dummy table, LAST_INSERT_ID() returns a unique id. The DELETE query merely keeps this dummy table from taking up too much space.
I recommend that you use a normal sequence-based bigint column. Then, on SELECT, add the base for the appropriate account type to the column.
PreparedStatement ps = con.prepareStatement("insert into emp(emp_code,emp_name,join_date,designation,birth_date,gender,mobile) values((select max(emp_code)+1 from emp),?,?,?,?,?,?)")
This query will definitely help..
I have a table with 3 fields: Id(PK,AI), Name(varchar(36)), LName(varchar(36)).
I have to insert name and last name, Id inserts automatically because of it's constraints,
Is There a way to Jump id auto increment value when it reaches 6?
for instance do this 7 times:
Insert Into table(Name, LName) Values ('name1', 'lname1') "And jump id to 7 if it is going to be 6"
It may sound stupid to do this but I have the doubt.
Also Jump and do not record id 6.
record only, 1-5, 7,8,9 and so on
What I want to achieve starts from a Union:
Select * From TableNames
Union All
Select * From TableNames_general
In the TableNames_general I assign it's first value so that when the user sees the table for the first time it will be displayed the record I inserted.
The problem comes when the user inserts a new record, if the Id of the inserted record is the same as the one I have inserted it will be duplicated, that is why I want to achieve when the users inserts one record and if the last insert id already exists just jump that record. this is because I must have different ids due to its relationship among child tables.
Identity column generate values for you, And its best left this way, You have the ability to insert specific values in Identity column but its best left alone and let it generate values for you.
Imagine you have inserted a value explicitly in an identity column and then later on Identity column generates the same value for you, you will end up with duplicates.
If you want to have your input in that column then why bother with identity column anyway ??
Well this is not the best practice but you can jump to a specific number by doing as follows:
MS SQL SERVER 2005 and Later
-- Create test table
CREATE TABLE ID_TEST(ID INT IDENTITY(1,1), VALUE INT)
GO
-- Insert values
INSERT INTO ID_TEST (VALUE) VALUES
(1),(2),(3)
GO
-- Set idnentity insert on to insert values explicitly in identity column
SET IDENTITY_INSERT ID_TEST ON;
INSERT INTO ID_TEST (ID, VALUE) VALUES
(6, 6),(8,8),(9,9)
GO
-- Set identity insert off
SET IDENTITY_INSERT ID_TEST OFF;
GO
-- 1st reseed the value of identity column to any smallest value in your table
-- below I reseeded it to 0
DBCC CHECKIDENT ('ID_TEST', RESEED, 0);
-- execute the same commad without any seed value it will reset it to the
-- next highest idnetity value
DBCC CHECKIDENT ('ID_TEST', RESEED);
GO
-- final insert
INSERT INTO ID_TEST (VALUE) VALUES
(10)
GO
-- now select data from table and see the gap
SELECT * FROM ID_TEST
If you query the database to get the last inserted ID, then you can check if you need to increment it, by using a parameter in the query to set the correct ID.
If you use MSSQL, you can do the following:
Before you insert check for the current ID, if it's 5, then do the following:
Set IDENTITY_INSERT to ON
Insert your data with ID = 7
Set IDENTITY_INSERT to OFF
Also you might get away with the following scenario:
check for current ID
if it's 5, run DBCC CHECKIDENT (Table, reseed, 6), it will reseed the table and in this case your next identity will be 7
If you're checking for current identity just after INSERT, you can use SELECT ##IDENTITY or SELECT SCOPE_IDENTITY() for better results (as rcdmk pointed out in comments)
Otherwise you can just use select: SELECT MAX(Id) FROM Table
There's no direct way to influence the AUTO_INCREMENT to "skip" a particular value, or values on a particular condition.
I think you'd have to handle this in an AFTER INSERT trigger. An AFTER INSERT trigger can't update the values of the row that was just inserted, and I don't think it can make any modifications to the table affected by the statement that fired the trigger.
A BEFORE INSERT trigger won't work either, because the value assigned to an AUTO_INCREMENT column is not available in a BEFORE INSERT trigger.
I don't believe there's a way to get SQL Server IDENTITY to "skip" a particular value either.
UPDATE
If you need "unique" id values between two tables, there's a rather ugly workaround with MySQL: roll your own auto_increment behavior using triggers and a separate table. Rather than defining your tables with AUTO_INCREMENT attribute, use a BEFORE INSERT trigger to obtain a value.
If an id value is supplied, and it's larger than the current maximum value from the auto_increment column in the dummy auto_increment_seq table, we'd need to either update that row, or insert a new one.
As a rough outline:
CREATE TABLE auto_increment_seq
(id INT NOT NULL PRIMARY KEY AUTO_INCREMENT) ENGINE=MyISAM;
DELIMITER $$
CREATE TRIGGER TableNames_bi
BEFORE INSERT ON TableNames
FOR EACH ROW
BEGIN
DECLARE li_new_id INT UNSIGNED;
IF ( NEW.id = 0 OR NEW.id IS NULL ) THEN
INSERT INTO auto_increment_seq (id) VALUES (NULL);
SELECT LAST_INSERT_ID() INTO li_new_id;
SET NEW.id = li_new_id;
ELSE
SELECT MAX(id) INTO li_max_seq FROM auto_increment_seq;
IF ( NEW.id > li_max_seq ) THEN
INSERT INTO auto_increment_seq (id) VALUES (NEW.id);
END IF;
END IF;
END$$
CREATE TRIGGER TableNames_ai
AFTER INSERT ON TableNames
FOR EACH ROW BEGIN
DECLARE li_max_seq INT UNSIGNED;
SELECT MAX(id) INTO li_max_seq FROM auto_increment_seq;
IF ( NEW.id > li_max_seq ) THEN
INSERT INTO auto_increment_seq (id) VALUES (NEW.id);
END IF;
END;
DELIMITER ;
The id column in the table could be defined something like this:
TableNames
( id INT UNSIGNED NOT NULL DEFAULT 0 PRIMARY KEY
COMMENT 'populated from auto_increment_seq.id'
, ...
You could create an identical trigger for the other table as well, so the two tables are effectively sharing the same auto_increment sequence. (With less efficiency and concurrency than an Oracle SEQUENCE object would provide.)
IMPORTANT NOTES
This doesn't really insure that the id values between the tables are actually kept unique. That would really require a query of the other table to see if the id value exists or not; and if running with InnoDB engine, in the context of some transaction isolation levels, we might be querying a stale (as in, consistent from the point in time at the start of the transaction) version of the other table.
And absent some additional (concurrency killing) locking, the approach outline above is subject to a small window of opportunity for a "race" condition with concurrent inserts... the SELECT MAX() from the dummy seq table, followed by the INSERT, allows a small window for another transaction to also run a SELECT MAX(), and return the same value. The best we can hope for (I think) is for an error to be thrown due to a duplicate key exception.
This approach requires the dummy "seq" table to use the MyISAM engine, so we can get an Oracle-like AUTONOMOUS TRANSACTION behavior; if inserts to the real tables are performed in the context of a REPEATABLE READ or SERIALIZABLE transaction isolation level, reads of the MAX(id) from the seq table would be consistent from the snapshot at the beginning of the transaction, we wouldn't get the newly inserted (or updated) values.
We'd also really need to consider the edge case of an UPDATE of row changing the id value; to handle that case, we'd need BEFORE/AFTER UPDATE triggers as well.
My idea was to have a table called "changelog_table" that had the following columns:
updated_table //the table being updated
updated_column //the column being updated
updated_row //the id of the row being updated
updated_content //this is what they updated the field to
updated_user //the user who updated
updated_datetime //the timestamp it was updated
I think this is both the minimum and maximum of what I'd really want, but I may be wrong.
Also...I do not understand, after weeks of reading, how to store variables (like "which table is being updated" and "which column is being updated" and so forth) in my trigger.
So let's say I had a table called "foo_table", with a column "bar_column", with a row "58008", that is being updated to "this is the new content", by user "peter_griffin", at 12/30/2013 at noon.
What would a trigger that could capture that look like?
You'll need to create separate triggers on each table for UPDATE (and, if so desired, for INSERT and DELETE too). They could each call the same stored procedure that does the actual logging.
The trigger can pass to the stored procedure a parameter containing the name of the table on which the operation is being performed (since the trigger is table-specific, it will know this - it'll have to be hardcoded); to detect which column(s) have been updated you'll need to compare, within each trigger, NEW.column with OLD.column for each column in the respective table.
For example:
CREATE TRIGGER upd_tbl_name AFTER UPDATE ON tbl_name FOR EACH ROW
CALL AuditLog('UPDATE', 'tbl_name', NEW.id, CONCAT_WS(',',
IF(NEW.columnA <=> OLD.columnA, NULL, CONCAT('columnA:=', NEW.columnA)),
IF(NEW.columnB <=> OLD.columnB, NULL, CONCAT('columnB:=', NEW.columnB)),
-- etc.
));
CREATE PROCEDURE AuditLog(
Action VARCHAR(10),
TableName VARCHAR(64),
RowID INT,
Columns TEXT,
)
INSERT INTO changelog_table VALUES (
Action,
TableName,
RowID,
Columns
USER(),
NOW(),
);
Say I have a MySQL table with an auto incrementing id field, then I insert 3 rows. Then, I delete the second row. Now the id's of the table go 1,3. Can I get MySQL to correct that and make it 1,2 without having to write a program to do so?
MySQL won't let you change the indexing of an Auto-Index column once it's created. What I do is delete the Auto-Index column and then add a new one with the same name, mysql will index the newly generated column with no gaps. Only do this on tables where the Auto-Index is not relevant to the rest of the data but merely used as a reference for updates and deletes.
For example I recently did just that for a table containing proverbs where the Auto-Index column was only used when I updated or deleted a proverb but I needed the Auto-Index to be sequential as the proverbs are pulled out via a random number between 1 and the count of the proverbs, having gaps in the sequence could have led to the random number pointing to a non-existant index.
HTH
Quoting from The Access Ten Commandments (and it can be extensible to other RDBMS: "Thou shalt not use Autonumber (or Auto Incremental) if the field is meant to have meaning for thy users".
The only alternative I can think of (using only MySQL) is to:
Create a trigger that adds the row number to a column (not the primary key)
Create a procedure to delete rows and update the row number (I couldn't make this work with triggers, sorry)
Example:
create table tbl_dummy(
id int unsigned not null auto_increment primary key,
row_number int unsigned not null default 0,
some_value varchar(100)
);
delimiter $$
-- This trigger will add the correct row number for each record inserted
-- to the table, regardless of the value of the primary key
create trigger add_row_number before insert on tbl_dummy
for each row
begin
declare n int unsigned default 0;
set n = (select count(*) from tbl_dummy);
set NEW.row_number = n+1;
end $$
-- This procedure will update the row numbers for the records stored
-- after the id of the soon-to-be-deleted record, and then deletes it.
create procedure delete_row_from_dummy(row_id int unsigned)
begin
if (select exists (select * from tbl_dummy where id = row_id)) then
update tbl_dummy set row_number = row_number - 1 where id > row_id;
delete from tbl_dummy where id = row_id;
end if;
end $$
delimiter ;
Notice that you'll be forced to delete the records one by one, and you'll be forced to get the correct primary key value of the record you want to delete.
Hope this helps
I have a mySQL db with duplicate records, as from the attached image.
I am asking for a query to delete all duplicate records based on date + time, for all tables (foreachtables) in db
Thanks
As far I could see, you dont have autoincrement primary key or foreign key.
If you dont have tables with foreign key or relation between, first you can list all your tables. After that, you can create a temporal "mirror" of one table (for eg, autogrill).
Then you can do a:
INSERT INTO TemporalTable
SELECT DISTINCT
or a
INSERT INTO TemporalTable
SELECT Id, Date, Time FROM autogrill GROUP BY Id, Date, Time HAVING COUNT(*) > 1
.
TRUNCATE or DELETE FROM
without where and then put again your data with
INSERT INTO autogrill
SELECT * FROM TemporalTable
BE AWARE if you have primary keys doing this.
How about you create and STORED PROCEDURE for this?
DELIMITER $$
CREATE PROCEDURE `DeleteDup`()
BEGIN
-- Drops the table.
DROP TABLE bad_temp;
-- Creates a temporary table for distincts record.
CREATE TABLE bad_temp(id INT, name VARCHAR(20));
-- Selects distinct record and inserts it on the temp table
INSERT INTO bad_temp(id,name) SELECT DISTINCT id,name FROM bad_table;
-- Delete All Entries from the table which contains duplicate
-- (you can add also condition on this)
DELETE FROM bad_table;
-- Selects all records from temp table and
-- inserts back in the orginal table
INSERT INTO bad_table(id,name) SELECT id,name FROM bad_temp;
-- Drops temporary table.
DROP TABLE bad_temp;
END$$
DELIMITER ;
Please change tablename and column name to your desired schema.
so when you finish creating your STORED PROCEDURE, you can use it like this:
CALL DeleteDup();
You can export your table using this request :
SELECT * FROM autogrill GROUP BY id
Then, empty your table, and import the export you made before. I don't know another easy way to erase duplicate entries using only a single request.
One easy way to do this is to copy all the distinct records into a new table or an export. Then delete all records in the original table and copy them back in.
Export NULL if table have autoincrement an for source use alias name, example :
INSERT INTO product
SELECT NULL,p.product_sku,
p.product_s_desc,
p.product_desc,
p.product_thumb_image,
p.product_full_image,
p.product_tech_data,
p.product_publish,
p.product_weight,
p.product_weight_uom,
p.product_length,
p.product_width,
p.product_height,
p.product_lwh_uom,
p.product_url,
p.product_in_stock,
p.product_available_date,
p.product_special,
p.create_date,
p.modify_date,
p.product_name,
p.attribute
FROM product AS p WHERE p.product_id=xxx;