I'm trying to create a new table called SITANAG with SQLTalk for Window. When i execute this command:
CREATE TABLE SITANAG
(
ANAGCOD INT NOT NULL UNIQuE,
PRIMARY KEY(ANAGCODE)
);
I get this error:
ANAGCOD INT NOT NULL UNIQUE,
^
Error: Missing right parenthesis
Someone know why this give error?
Thank for your time
You dont have to make the column as NOT NULL and UNIQUE explicitly. Primary key is by default NOT NULL and UNIQUE. Try this:
CREATE TABLE SITANAG
(
ANAGCOD INT,
PRIMARY KEY(ANAGCOD )
);
DEMO
On a side note you have a typo error when you are naming your column in primary key, it should be either ANAGCOD or ANAGCODE
The manual says:
A PRIMARY KEY is a unique index where all key columns must be defined
as NOT NULL. If they are not explicitly declared as NOT NULL, MySQL
declares them so implicitly (and silently).
Related
CREATE TABLE hoofdtoonder
(
id INT NOT NULL,
idondersoorten INT FOREIGN KEY REFERENCES `ondersoort`(`id`) NOT NULL,
)
//making table but the error is with the references its on a mysql database someone please help
It says error at FOREIGN KEY REFERENCES ondersoort(id) NOT NULL. But I don't know what's wrong with the syntax.
There are several things wrong here:
First, for an inline constraint, you don't need to specify foreign key, just references.
The not null clause should come before the references clause.
You have a redundant comma at the end of the last column's specification.
To put it all together:
CREATE TABLE hoofdtoonder (
id INT NOT NULL,
idondersoorten INT NOT NULL REFERENCES `ondersoort`(`id`)
);
MySQL does not support inline foreign key references.
It's true that the SQL language allows for syntax like #Mureinik suggested:
idondersoorten INT NOT NULL REFERENCES `ondersoort`(`id`)
But you will find that MySQL parses this and ignores it. InnoDB does not support inline foreign key syntax. If you now run SHOW CREATE TABLE hoofdtoonder, it'll show this:
CREATE TABLE `hoofdtoonder` (
`id` int(11) NOT NULL,
`idondersoorten` int(11) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
Where did the REFERENCES go? It was silently discarded. This is actually a beef I have with MySQL, that it recognizes some valid constraint syntax, but ignores it. It doesn't even show you a warning. It just defines the table without the constraint.
In MySQL, you must declare a foreign key as a table-level constraint, like this:
CREATE TABLE hoofdtoonder (
id INT NOT NULL,
idondersoorten INT NOT NULL,
FOREIGN KEY (idondersoorten) REFERENCES `ondersoort`(`id`)
);
CREATE TABLE table_name(
id INT NOT NULL PRIMARY KEY,
Name TEXT,
Post TEXT,
Age INT LEN<68
)
How do i create that Post attribute where the constraint must be either Manager or clerk.
MySQL does not enforce check constraints. This leaves you with three options:
You can create an enum with two values, 'manager' and 'clerk'.
You can create a reference table that has two rows, and use a foreign key reference.
You can create a trigger to check the values.
By the way, this line:
Age INT LEN<68
is not syntactically correct.
CREATE TABLE `movies`.`movie`
( `movie_id` INT(3) NULL AUTO_INCREMENT, `movie_name` VARCHAR(25) NULL,
`movie_embedded_id` VARCHAR(50) NULL, `rating_no` INT(3) NULL,
`movie_description` VARCHAR(50) NULL, PRIMARY KEY (`movie_id`(3))) ENGINE = InnoDB;
I keep getting this error:
#1089 - Incorrect prefix key; the used key part isn't a string, the used length is longer than the key part, or the storage engine doesn't
support unique prefix keys.
but I've got no idea what it means, anyone have a clue?
With the part
PRIMARY KEY (`movie_id`(3))
you are telling mysql to create a sub part key* on the first 3 Bytes of movie id. This only works for string types.
You need to use
PRIMARY KEY (`movie_id`)
without providing a length.
*Is this sure the query resulting in the error? Never saw that on a primary key, its used for indexes.
after selecting PRIMARY KEY when you create table, don't input any value in pop dialog
You can also get this error when creating an index if you specify a prefix length that is longer than the length of the actual column. If you tried to create an index containing someColumn(20) but in the table someColumn is VARCHAR(15), then this error will occur.
For the primary key do not enter any length of type.
Example:
int()
SQL query:
ALTER TABLE `blog` CHANGE `id` `id` BIGINT NOT NULL AUTO_INCREMENT
MySQL said:
#1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key
I am trying to create a blog, and I got the code done. Now, I need to make the id auto increase, but I get this error. Why am I getting this?
MySQL is returning that error (most likely) because there is no unique index defined on the id column. (MySQL requires that there be a unique index. The other possibility, which you would have already figured out, is that there can be only one column defined as AUTO_INCREMENT within the table.)
To get that column to be an AUTO_INCREMENT, you can add either a UNIQUE constraint or a PRIMARY KEY constraint on the id column. For example:
ALTER TABLE `blog` ADD CONSTRAINT `blog_ux` UNIQUE (`id`) ;
(Note that this statement will return an error if any duplicate values exist for the id column.)
Alternatively, you can make the id column the PRIMARY KEY of the table (if the table doesn't already have a PRIMARY KEY constraint defined).
ALTER TABLE `blog` ADD PRIMARY KEY (`id`) ;
(Note that this statement will return an error if any duplicate value exist for the id column, OR if there are any NULL values stored in that column, of if there is already a PRIMARY KEY constraint defined on the table.)
MySQL requires you to make auto increment column the primary key of a table. Add the primary key constraint at the end
ALTER TABLE `blog` MODIFY COLUMN `id` BIGINT NOT NULL AUTO_INCREMENT primary key
To resolve #1075 error message you need to mark atleast one column as primary_key or unique_key. that you have forgot to do.
By defining Primary _key on ID column my error is resolved guys.
thanks
What's the point of adding NOT NULL to a primary key field? Primary key is already not null + unique.
Here is an example:
CREATE TABLE student (
id int(11) AUTO_INCREMENT NOT NULL,
name varchar(255),
PRIMARY KEY(id)
)
Why not to define it like this instead:
CREATE TABLE student (
id int(11) AUTO_INCREMENT,
name varchar(255),
PRIMARY KEY(id)
)
They are the same. Primary key got NOT NULL automatically.
You are asking, why do people bother adding the NOT NULL when it is unnecessary? Just because it is good style, I guess. And makes it explicit to the reader.
NULL is not equivalent to NULL(as NULL indicates an unknown or absent value), so you will be permitted to have multiple records that have NULL for the id, even though there's a primary key / unique constraint defined, hence the use of NOT NULL. That's if MySql even allows you to define a primary key on a nullable field.
In addition, as a primary key is often used in a foreign key in other tables, having one or more NULL values wouldn't make sense.
If PRIMARY KEY is declared without NOT NULL, NOT NULL is added to PRIMARY KEY implicitly so PRIMARY KEY with or without NOT NULL is the same.
The MySQL documentation says as shown below:
A unique index where all key columns must be defined as NOT NULL. If
they are not explicitly declared as NOT NULL, MySQL declares them so
implicitly (and silently). A table can have only one PRIMARY KEY. The
name of a PRIMARY KEY is always PRIMARY, which thus cannot be used as
the name for any other kind of index.
And also, the MySQL documentation says as shown below:
The primary key for a table represents the column or set of columns
that you use in your most vital queries. It has an associated index,
for fast query performance. Query performance benefits from the NOT
NULL optimization, because it cannot include any NULL values. ...