I'm currently having issues with inserting values into a database table that uses a foreign key from another table to align the is together. The tables are pretty simple. One holds information about a project, and the other hold values for the project images. Here they are in detail.
The projects table
project_id int(50) PRIMARY KEY NOT NULL AUTO_INCREMENT,
project_name varchar(50) NOT NULL,
project_permitted timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT "The date that the project took place.",
project_in varchar(50) NOT NULL COMMENT 'The place where the project took place (ie the city and state).',
project_type varchar(50) NOT NULL COMMENT 'The project type (ie residentual, commercial, etc).',
project_description longtext,
project_published timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
Here is the second table called project_images
image_id int(50) PRIMARY KEY NOT NULL AUTO_INCREMENT,
project_id int(50),
image_url varchar(50) NOT NULL,
CONSTRAINT fk_projects FOREIGN KEY (project_id) REFERENCES projects(project_id)
What I am trying to do is insert values into the second table using the project_id from the projects table using a subquery. That query looks like this:
insert into project_images (project_id, project_url, project_description)
values (
(select project_id from projects where project_name = 'The Venue'),
"images/theVenue.png",
"The Venue: an appartment complex in Austin, Texas."
)
With this query I keep getting an error that says
something to the effect of "You are missing a comma or closing bracket
near project_id.
Can anyone help or point out the best way to handle this situation.
Modify your query to be like
insert into project_images (project_id, project_url, project_description)
select project_id ,
"images/theVenue.png",
"The Venue: an appartment complex in Austin, Texas."
from projects where project_name = 'The Venue';
After looking into this question a bit more, it seems that you cannot use a subquery the way I am using it to get the value of a column, However, the column can be inserted directly so long as the foreign key points to a primary key from another table that has already be inserted. The whole point to using this query was for a PHP project, so I guess I'll just do a select query in a project to get its ID then add that to the sql that queries the project_images table. This seems to be the only way to do that.
Related
i have created a table in mysql named as student with 2 columns named as "S-id int not null auto_increment 14012040" and "S-name varchar(45) not null unique" "primary key(S-id)"....
the table was successfully created..but after inserting one record into db ,on the next insertion it shows error like "dupliction of primary key is not allowed"...plz hlp me whta should i do..
in th below i am posting the screen shots....
creating table.
[1st insertion successfully addesd][2]
getting error
Your primary key S-id has a default value (14012040).
You only inserts values for S-name and studentcol columns therefore it will use the S-ids default value again and again.
When it runs first it can use the default value because it is not exists in the table. But second time it will throw an error.
You should use auto increment for S-id as Álvaro Touzón said.
UPDATE:
According to your comment, here is the working create script:
CREATE TABLE student (
S_id INT NOT NULL AUTO_INCREMENT
,S_name VARCHAR(45) NOT NULL
,PRIMARY KEY (S_id)
,UNIQUE INDEX S_name_UNIQUE(S_name ASC)
) AUTO_INCREMENT=14012040;
Working SQL fiddle here.
I'm a totally MySQL newcomer. Sr if my question is quite obvious. I got 2 tables
CREATE TABLE tbl_addresses(
PK_ADDRESS_ID int NOT NULL AUTO_INCREMENT,
house_number int NOT NULL,
street varchar(35),
district varchar(35),
city varchar(35),
postcode varchar(8),
PRIMARY KEY (PK_ADDRESS_ID)
);
CREATE TABLE tbl_people(
PK_PERSON_ID int NOT NULL AUTO_INCREMENT,
title varchar(6) NOT NULL, # Master / Mister therefor 6 is max
forename varchar(35) NOT NULL,
surname varchar(35) NOT NULL,
date_of_birth DATE NOT NULL,
contact_number varchar(12) NOT NULL,
FK_ADDRESS_ID int NOT NULL,
PRIMARY KEY (PK_PERSON_ID),
FOREIGN KEY (FK_ADDRESS_ID) REFERENCES tbl_addresses (PK_ADDRESS_ID)
);
and I'm trying to import data into these tables from Java using below syntaxes
INSERT INTO tbl_addresses (house_number,street,district,city,postcode) VALUES ('1','abc','','abc','abc');
INSERT INTO tbl_people (title,forename,surname,date_of_birth,contact_number) VALUES ('Mr','Tri ','Nguyen','1991-1-1','0123456789');
I got an error Field 'FK_ADDRESS_ID'doesn't have a default value and data actually goes into tbl_addresses but not tbl_people. Am I missing anything? Thanks in advance!
This error is being caused by that you labelled the FK_ADDRESS_ID field in the tbl_people table as NOT NULL, yet you are trying to do an INSERT without specifying a value for this column.
So something like this would work without error:
INSERT INTO tbl_people (title, forename, surname, date_of_birth,
contact_number, FK_ADDRESS_ID)
VALUES ('Mr', 'Tri', 'Nguyen', '1991-1-1', '0123456789', 1);
You could also specify a default value for FK_ADDRESS_ID (the error message you got alluded to this). Here is how you could adda default value:
ALTER TABLE tbl_people MODIFY COLUMN FK_ADDRESS_ID int NOT NULL DEFAULT 1
But because FK_ADDRESS_ID is a key into another table, the value should really be based on the primary key in tbl_addresses.
The fact that you are using a foreign key isn't the reason that you are getting this error. Let's take a look at your column definition.
FK_ADDRESS_ID int NOT NULL,
This is not null but does not a default. Now a look at your insert statement
INSERT INTO tbl_people (title,forename,surname,date_of_birth,contact_number)
FK_ADDRESS_ID isn't in your column list but it cannot be null and doesn't have a default so what can mysql do? Produce an error of course.
The best bet is to define that column as nullable.
Let's revisit the foreign key constraint.
FOREIGN KEY (FK_ADDRESS_ID) REFERENCES tbl_addresses (PK_ADDRESS_ID)
What this really says is that if you asign a value to FK_ADDRESS_ID that value should be present in PK_ADDRESS_ID column in tbl_address
as a side note, it's customary to use lower case for table/column names.
Sorry if this is an easy question, I am coming to MySQL from SQL Server.
When I execute my create statement it contains nvarchar but commits to the database as varchar. Even in my alter statement afterwards the column does not change at all. Does the collation or DB engine make a difference?
During execution I am not encountering any issues in results, other than the fact the column changes datatype. I attached a screencast of my activity http://screencast.com/t/wc94oei2
I have not been able to find anyone with similar issues through my Google searches
Did you mean, this..
CREATE TABLE stars (
idstars int(11) NOT NULL AUTO_INCREMENT,
Name nvarchar(200) DEFAULT NULL,
PRIMARY KEY (idstars),
UNIQUE KEY Name_UNIQUE (Name)
)
----turns to---
CREATE TABLE stars (
idstars int(11) NOT NULL AUTO_INCREMENT,
Name varchar(200) DEFAULT NULL,
PRIMARY KEY (idstars),
UNIQUE KEY Name_UNIQUE (Name)
)
I have created a table empInfo as follow
CREATE TABLE empInfo (
empid INT(11) PRIMARY KEY AUTO_INCREMENT ,
firstname VARCHAR(255) DEFAULT NULL,
lastname VARCHAR(255) DEFAULT NULL
)
Then I run below Insert statements :-
INSERT INTO empInfo VALUES(NULL , 'SHREE','PATIL');
INSERT INTO empInfo(firstname,lastname) VALUES( 'VIKAS','PATIL');
INSERT INTO empInfo VALUES(NULL , 'SHREEKANT','JOHN');
I thought first or Third SQL will fail as empid is PRIMARY KEY and We are trying to insert NULL for empid .
But MYSQL proved me wrong and all 3 queries ran successfully .
I wanted to know Why it is not failing when trying to insert NULL in empid column ?
Final Data available in table is as below
empid firstname lastname
1 SHREE PATIL
2 VIKAS PATIL
3 SHREEKANT JOHN
I can figure out that it has something releted to AUTO_INCREMENT But I am not able to figure out reason for it . Any pointers on this .
This behaviour is by design, viz inserting 0, NULL, or DEFAULT into an AUTO_INCREMENT column will all trigger the AUTO_INCREMENT behaviour.
INSERT INTO empInfo VALUES(DEFAULT, 'SHREEKANT','JOHN');
INSERT INTO empInfo VALUES(NULL, 'SHREEKANT','JOHN');
INSERT INTO empInfo VALUES(0, 'SHREEKANT','JOHN');
and is commonplace practice
Note however that this wasn't however always the case in versions prior to 4.1.6
Edit
Does that mean AUTO_INCREMENT is taking precedance over PRIMARY KEY?
Yes, since the primary key is dependent on the AUTO_INCREMENT delivering a new sequence prior to constraint checking and record insertion, the AUTO_INCREMENT process (including the above re-purposing of NULL / 0 / DEFAULT) would need to be resolved prior to checking PRIMARY KEY constraint in any case.
If you remove the AUTO_INCREMENT and define the emp_id PK as INT(11) NULL (which is nonsensical, but MySql will create the column this way), as soon as you insert a NULL into the PK you will get the familiar
Error Code: 1048. Column 'emp_id' cannot be null
So it is clear that the AUTO_INCREMENT resolution precedes the primary key constraint checks.
It is exactly because of the auto increment. As you can see, no empid values are null in the db. That is the purpose of auto increment. Usually you would just not include that column in the insert, which is same as assigning null
As per the documentation page:
No value was specified for the AUTO_INCREMENT column, so MySQL assigned sequence numbers automatically. You can also explicitly assign 0 to the column to generate sequence numbers. If the column is declared NOT NULL, it is also possible to assign NULL to the column to generate sequence numbers.
So, because you have an auto increment null-allowed field, it ignores the fact that you're trying to place a NULL in there, and instead gives you a sequenced number.
You could just leave it as is since, even without the not null constraint, you can't get a NULL in there, because it will auto-magically convert that to a sequenced number.
Or you can change the column to be empid INT(11) PRIMARY KEY AUTO_INCREMENT NOT NULL if you wish, but I still think the insert will allow you to specify NULLs, converting them into sequenced numbers in spite of what the documentation states (tested on sqlfiddle in MySQL 5.6.6 m9 and 5.5.32).
In both cases, you can still force the column to a specific (non-zero) number, constraints permitting of course.
CREATE TABLE empInfo (
empid INT(11) PRIMARY KEY AUTO_INCREMENT NOT NULL,
firstname VARCHAR(255) DEFAULT NULL,
lastname VARCHAR(255) DEFAULT NULL
)
Not sure but i think it will work :)
I have a table with 2 primary keys(user_id,post_id)
I want to insert row only if table havn't a row with this user id and post id
And if previous data exist for this keys , only that row update with the new data
I wrote this query:
INSERT INTO trust_list(`user_id`,`post_id`,`post_per`,`comment_per`,`cat_per`)
VALUES (7,1,'000','000','000')
ON DUPLICATE KEY UPDATE `post_per`='000',`comment_per`='000',`cat_per`='000'
For example if this row exist in the table:
user_id:5
post_id:1
post_per:001
comment_per:111
cat_per:101
Then ,when i execute the above query , mysql update this row,only because post_id of this row is "1"
Whereas mysql should not update this row .
I don't understand what's the problem.
DESC trust_list
result of above query is:
Field Type Null Key Default Extra
user_id int(11) NO PRI NULL
post_id int(4) NO PRI NULL
post_per tinytext YES NULL
comment_per tinytext YES NULL
cat_per tinytext YES NULL
=================
Thanks to all of my friends
When i decide to drop table and ceate it again ,I get an export from this table
and review the .sql file,i see this:
CREATE TABLE IF NOT EXISTS `trust_list` (
`user_id` int(11) NOT NULL,
`post_id` int(11) NOT NULL,
`post_per` tinytext COLLATE utf8_estonian_ci ,
`comment_per` tinytext COLLATE utf8_estonian_ci ,
`cat_per` tinytext COLLATE utf8_estonian_ci ,
PRIMARY KEY (`idea_id`,`user_id`),
UNIQUE KEY `idea_id` (`idea_id`)
)
apparently , problem is from the UNIQUE KEY ,I remove it from file ,and then drop trust_list table ,and then import .sql file
So with this ,my problem solved
Thanks again
There is something wrong with your table schema.
Assuming that your schema defined something like this
CREATE TABLE trust_list(
`user_id` int,
`post_id` int,
`post_per` varchar(12),
`comment_per` varchar(12),
`cat_per`varchar(12),
PRIMARY KEY(`user_id`, `post_id`)
);
here is SQLFiddle that demonstrates that your INSERT statement works on it just fine.
Consider to show your CREATE TABLE statement to help you find the problem, or just change PK as showed.
I think your problem is your understanding of primary key. You can't have two primary keys in the table, only one. What you have probably is a primary key that consists of two columns. In that case you only get a key violation when both columns match.
Solution:
Introduce unique indices for both columns. Or - better - change the primary key to be only one of the two columns and set the other column to have a unique index.
Thanks to peterem here is the sqlfiddle with my solution.