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newbie and appreciate your help.
So I have the below employee table with emp_id as primary and auto incremental. I would like to avoid users from inserting new record when the combination of first_name and last_name already exists.
I am connecting the DB to windows from (VB.net), ultimately I would like to display a message saying that the user's first and last name already exists. I could do it progrmaticly by vb code, however i am wondering if I can setup this check at the database level.
CREATE TABLE `employee` (
`emp_id` smallint(5) unsigned NOT NULL AUTO_INCREMENT,
`first_name` varchar(20) NOT NULL,
`middle_name` varchar(30) DEFAULT NULL,
`last_name` varchar(20) NOT NULL,
`date_of_birth` varchar(45) NOT NULL,
`gender` char(6) NOT NULL,
PRIMARY KEY (`emp_id'),
UNIQUE KEY `employee_id_UNIQUE` (`emp_id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8
You can make constraints on sets of columns like this:
CREATE TABLE `employee` (
`emp_id` smallint(5) unsigned NOT NULL AUTO_INCREMENT,
`first_name` varchar(20) NOT NULL,
`middle_name` varchar(30) DEFAULT NULL,
`last_name` varchar(20) NOT NULL,
`date_of_birth` varchar(45) NOT NULL,
`gender` char(6) NOT NULL,
PRIMARY KEY (`emp_id'),
UNIQUE KEY `employee_name_UNIQUE` (`first_name`, `last_name`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8
That means if the combination of first_name and last_name already exists in the database, if you try to insert a new row with the same values, it results in a duplicate key error.
You need to write code in your application to handle that error, and then display an appropriately helpful message to the user.
CREATE TABLE IF NOT EXISTS customers_data (
id int(20) UNSIGNED AUTO_INCREMENT PRIMARY KEY NOT NULL,
INVOICE_ID varchar(50) NOT NULL,
_NAME varchar(255) NOT NULL,
MOBILE bigint(12) NOT NULL,
GSTIN varchar(20) NOT NULL,
_ADDRESS varchar(255) NOT NULL,
EMAIL varchar(255) NOT NULL,
_STATE varchar(50) NOT NULL,
MODE varchar(10) NOT NULL,
_DATE date NOT NULL DEFAULT current_timestamp(),
total_qty int(11) NOT NULL,
total_amount decimal(40,2) NOT NULL,
total_sc_gst decimal(30,2) NOT NULL,
Round_Off float(2,2) NOT NULL,
grand_total decimal(50,0) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
customer_data created sucessfully.
But there is an error in order_data regarding foreign key. Remember I want to create these two table in a same time.
CREATE TABLE IF NOT EXISTS order_data (
id int(20) UNSIGNED AUTO_INCREMENT PRIMARY KEY NOT NULL,
cus_id int(20) NOT NULL,
ITEM varchar(255) NOT NULL,
HSN varchar(50) NOT NULL,
QTY int(15) NOT NULL,
RATE decimal(40,2) NOT NULL,
S_C_GST decimal(30,2) NOT NULL,
TOTAL decimal(50,2) NOT NULL,
_DATE timestamp NOT NULL DEFAULT current_timestamp(),
FOREIGN KEY(cus_id) REFERENCES customers_data(id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
I got this error.
#1005 - Can't create table test. (errno: 150 "Foreign
key constraint is incorrectly formed")
I think you are using MySQL. You have not used Constraint with Foreign Key. Try the below query.
CREATE TABLE IF NOT EXISTS order_data (
id int(20) UNSIGNED AUTO_INCREMENT PRIMARY KEY NOT NULL,
cus_id int(20) NOT NULL,
ITEM varchar(255) NOT NULL,
HSN varchar(50) NOT NULL,
QTY int(15) NOT NULL,
RATE decimal(40,2) NOT NULL,
S_C_GST decimal(30,2) NOT NULL,
TOTAL decimal(50,2) NOT NULL,
_DATE timestamp NOT NULL DEFAULT current_timestamp(),
**CONSTRAINT <FK_NAME>** FOREIGN KEY(cus_id) REFERENCES customers_data(id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
Making the table "at the same time" is not the problem you need to solve, (it's not possible anyway).
You can't make a foreign key if the data type is different from the data type of the referenced column.
order_data.cus_id is an INT column.
customers_data.id is an INT UNSIGNED column.
Change either one or the other data type, so they are the same.
I have 2 tables 'open_invoices' and 'paid_invoices' with the below structures:
CREATE TABLE `open_invoices` (
`id` int(11) UNSIGNED NOT NULL AUTO_INCREMENT,
`unique_identifier` varchar(255) NOT NULL,
`insert_date` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
`cust_nbr` int(11) NOT NULL,
`location` varchar(10) NOT NULL,
`company` varchar(10) NOT NULL,
`invoice_nbr` int(11) NOT NULL,
`future_letter` varchar(1) NOT NULL,
`invoice_total` decimal(8,2) NOT NULL,
`invoice_payments` decimal(8,2) NOT NULL,
`record_type` int(11) NOT NULL,
`terms_desc` varchar(255) NOT NULL,
`due_date` varchar(8) NOT NULL,
`discount_date` varchar(8) NOT NULL,
`orig_disc_avail` decimal(8,2) NOT NULL,
`cust_po` varchar(10) NOT NULL,
`invoice_date` varchar(8) NOT NULL,
`status` int(11) NOT NULL,
`check_no` varchar(10) NOT NULL,
`last_pay_date` varchar(8) NOT NULL,
`as_of_date` varchar(8) NOT NULL,
`as_of_time` varchar(11) NOT NULL,
`remaining` varchar(1) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `unique_identifier` (`unique_identifier`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `paid_invoices` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`date_change` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
`invoice_date` varchar(8) NOT NULL,
`unique_identifier` varchar(255) NOT NULL,
`amount_paid` decimal(8,2) NOT NULL,
`amount_left` decimal(8,2) NOT NULL,
`payment_type` varchar(2) NOT NULL,
`last4` varchar(255) NOT NULL,
`transac_id` varchar(255) NOT NULL,
`customer_id` varchar(255) NOT NULL,
`payment_P_F` varchar(1) NOT NULL,
PRIMARY KEY (`id`),
FOREIGN KEY (unique_identifier)
REFERENCES open_invoices (unique_identifier)
ON DELETE CASCADE
ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
I'm trying to insert a row in 'paid_invoices' like below:
INSERT INTO `paid_invoices` (`invoice_date`, `unique_identifier`, `amount_paid`, `amount_left`, `payment_type`, `last4`, `transac_id`, `customer_id`, `payment_P_F`) VALUES ('07/19/18', '126_89948_2576', 0, '37.45', '', '', '', '13776', 'P')
I get the below error:
Error Number: 1452
Cannot add or update a child row: a foreign key constraint fails (`accounts_receivables`.`paid_invoices`, CONSTRAINT `paid_invoices_ibfk_1` FOREIGN KEY (`unique_identifier`) REFERENCES `open_invoices` (`unique_identifier`))
INSERT INTO `paid_invoices` (`invoice_date`, `unique_identifier`, `amount_paid`, `amount_left`, `payment_type`, `last4`, `transac_id`, `customer_id`, `payment_P_F`) VALUES ('07/19/18', '126_89948_2576', 0, '37.45', '', '', '', '13776', 'P')
If I search on google, it says that the foreign key 126_89948_2576 was not found in the table 'open_invoices'.
When I do SELECT * FROM open_invoices WHERE id = 2576 I see the row with the foreign key 126_89948_2576 as shown in the picture below :
[![query 1][1]][1]
but when I do this query SELECT * FROM open_invoices WHERE unique_identifier = '126_89948_2576' I get no result see capture below:
[![query 2][2]][2]
I'm sure there is no extra blank space in the value saved for foreign key 126_89948_2576.
What is going on please? Is there a bug in the version of MySQL I'm using?
Server: Localhost via UNIX socket
Server type: MySQL
Server version: 5.6.40 - MySQL Community Server (GPL)
Protocol version: 10
Thanks.
[1]: https://i.stack.imgur.com/L2QDX.png
[2]: https://i.stack.imgur.com/T9Fz5.png
It seems you are using wrong divider symbols, "_" instead of "-" in your query. Try unique_identifier = '126-89948-2576'
Because the underscore _ is a wildcard like the percent %, except that it only looks for one character.
SQL pattern matching enables you to use "_" to match any single character and "%" to match an arbitrary number of characters (including zero characters).
you can use
SELECT * FROM open_invoices WHERE unique_identifier like '%126\_89948\_2576%'
i want to change database of my simple application from mysql to sqlite, this is my sql command :
CREATE TABLE `Todo` (
`Id` int(11) NOT NULL AUTO_INCREMENT,
`Title` varchar(255) DEFAULT NULL,
`Category` varchar(255) DEFAULT NULL,
`State` varchar(255) DEFAULT NULL,
PRIMARY KEY (`Id`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
im try to create sqllite but return me this error : Error: near "AUTO_INCREMENT": syntax error how i can fix it ?
Instead of using primary key separately, please mention it with your AUTO INCREMENT key
CREATE TABLE `Todo` (
`Id` integer primary key AUTOINCREMENT,
`Title` varchar(255) DEFAULT NULL,
`Category` varchar(255) DEFAULT NULL,
`State` varchar(255) DEFAULT NULL
)
I am working on magento platform.I face a problem regarding values insertion to specific field: My query run perfect but one specific column not working for any query.I try my best but didn't find why .When i change the column type from int to varchar type it works.This is my table structure.
CREATE TABLE `followupemails_emaillogs` (
`id` int(8) NOT NULL AUTO_INCREMENT,
`schedule_time` datetime DEFAULT NULL,
`sent_time` datetime DEFAULT NULL,
`email_status` varchar(100) DEFAULT NULL,
`client_name` varchar(250) DEFAULT NULL,
`client_email` varchar(250) DEFAULT NULL,
`followupemails_id` int(11) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=30 DEFAULT CHARSET=latin1.
the "followupemails_id" column not working in insert and update query.This is one update query where record exist that id(29). UPDATE followupemails_emaillogs SET followupemails_id=5 WHERE id =29.
This is insertion query INSERT INTO followupemails_emaillogs SET followupemails_id=4, schedule_time='2013-10-23 08:10:00', email_status='pending', client_name='ayaz ali'.this works fine on fiddle but not on my sqlyog ? what could be the issue.At last i find query that work perfect
.INSERT INTO followupemails_emaillogs (followupemails_id,schedule_time,email_status,client_name,client_email) VALUES (26,'2013-10-23 08:10:00','pending','ayaz ali','mamhmood#yahoo.com');
Can anyone tell me why set query not working but second query works perfect.so that i can accept his answer.Thanks for all your help
Try like this
To Create,
CREATE TABLE followupemails_emaillogs (
id int(8) NOT NULL AUTO_INCREMENT PRIMARY KEY,
schedule_time datetime DEFAULT NULL,
sent_time datetime DEFAULT NULL,
email_status varchar(100) DEFAULT NULL,
client_name varchar(250) DEFAULT NULL,
client_email varchar(250) DEFAULT NULL,
followupemails_i int(11) DEFAULT NULL,
UNIQUE (id)
)
To Insert,
INSERT INTO followupemails_emaillogs (schedule_time,sent_time,email_status,client_name,client_email,followupemails_i)
VALUES
('2012-05-05','2012-05-06',"sent","sagar","sagar#xxxx.com",2)
the whole query is ok
CREATE TABLE `followupemails_emaillogs` (
`id` int NOT NULL AUTO_INCREMENT,
`schedule_time` datetime DEFAULT NULL,
`sent_time` datetime DEFAULT NULL,
`email_status` varchar(100) DEFAULT NULL,
`client_name` varchar(250) DEFAULT NULL,
`client_email` varchar(250) DEFAULT NULL,
`followupemails_id` int DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=30 DEFAULT CHARSET=latin1.
but at the last there is dot which is actually error so remove the dot and create the table
latin1.
so remove the dot sign and not null in id filed use this line by default fields are null so don't use default null
id int (8) AUTO_INCREMENT
CREATE TABLE `followupemails_emaillogs` (
`id` int (8) AUTO_INCREMENT,
`schedule_time` datetime DEFAULT NULL,
`sent_time` datetime DEFAULT NULL,
`email_status` varchar(100),
`client_name` varchar(250),
`client_email` varchar(250),
`followupemails_id` int,
PRIMARY KEY (`id`),
UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=30 DEFAULT CHARSET=latin1
don't need (11) in the sql query for int operator , This get for length of the nvarchar,varchar datatype column only not a int datatype,So change and write int instead of int(11) and int(8)
Try this query instead of your query
CREATE TABLE `followupemails_emaillogs` (
`id` int NOT NULL AUTO_INCREMENT,
`schedule_time` datetime DEFAULT NULL,
`sent_time` datetime DEFAULT NULL,
`email_status` varchar(100) DEFAULT NULL,
`client_name` varchar(250) DEFAULT NULL,
`client_email` varchar(250) DEFAULT NULL,
`followupemails_id` int DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=30 DEFAULT CHARSET=latin1.