http://www.go4expert.com/forums/showthread.php?t=13386
im following the article above and i am getting error at the first quoted code
#1049 - Unknown database 'library'
CREATE TABLE `library`.`books` (
`id` INT UNSIGNED NOT NULL AUTO_INCREMENT ,
`name` VARCHAR( 150 ) NOT NULL ,
`author_id` INT UNSIGNED NOT NULL ,
PRIMARY KEY ( `id` ) ,
INDEX ( `author_id` )
) ENGINE = INNODB
the other one generates with no problem but this one, why?
Your table name is prepended with the database name "library". Probably your DB is named differently. If you're executing within the DB that you're using just remove the "library." prefix.
CREATE TABLE `books` (
...
Remove the "library" part from the CREATE TABLE statement. The other block in that article works because it doesn't reference "library".
Remove the library. - just use what ever database you're using, ie
CREATE TABLE books (...
And while you're at it, remove all those unnecessary backticks - they are only required when using reserved words (which you should avoid like the plague anyway)
The table authors will be created in your default/current database, here the database library is to be used, but it hasn't been created. You should make a library database.
CREATE DATABASE library
Using a differently named database, or removing library from the create table statement may cause problems further down the tutorial.
Related
Im revisiting my database and noticed I had some primary keys that were of type INT.
This wasn't unique enough so I thought I would have a guid.
I come from a microsoft sql background and in the ssms you can
choose type to "uniqeidentifier" and auto increment it.
In mysql however Ive found that you have to make triggers that execute on insert for the tables you want
to generate a guide id for. Example:
Table:
CREATE TABLE `tbl_test` (
`GUID` char(40) NOT NULL,
`Name` varchar(50) NOT NULL,
PRIMARY KEY (`GUID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
Trigger:
CREATE TRIGGER `t_GUID` BEFORE INSERT ON `tbl_test`
FOR EACH ROW begin
SET new.GUID = uuid();
Alternatively you have to insert the guid yourself in the backend.
Im no DB expert but still remember that triggers cause performance problems.
The above is something I found here and is 9 years old so I was hoping something has changed?
As far as stated in the documentation, you can use uid() as a column default starting version 8.0.13, so something like this should work:
create table tbl_test (
guid binary(16) default (uuid_to_bin(uuid())) not null primary key,
name varchar(50) not null
);
This is pretty much copied from the documentation. I don't have a recent enough version of MySQL at hand to test this.
You can make a
INSERT INTO `tbl_test` VALUES (uuid(),'testname');
This would generate a new uuid, when you call it.
Or you can also use the modern uuid v4 by using one of these functions instead of the standard uuid(), which is more random than the uuid in mysql
How to generate a UUIDv4 in MySQL?
You can use since 8.0.13
CREATE TABLE t1 (
uuid_field VARCHAR(40) DEFAULT (uuid())
);
But you wanted more than unique, but here are only allowed internal functions and not user defined as for uuid v4, for that uyou need the trogger
As per the documentation, BINARY(x) adds some hidden padding bytes to the end of each entry, & VARCHAR(40) also wastes space by not being encoded directly in binary. Using VARBINARY(16) would be more efficient.
Also, more entropy (unguessability / security) per byte is available from RANDOM_BYTES(16) than standardized UUIDs, because they use some sections to encode constant metadata.
Perhaps the below will work for your needs.
-- example
CREATE TABLE `tbl_test` (
`GUID` VARBINARY(16) DEFAULT (RANDOM_BYTES(16)) NOT NULL PRIMARY KEY,
`Name` VARCHAR(50) NOT NULL
);
Im revisiting my database and noticed I had some primary keys that were of type INT.
This wasn't unique enough so I thought I would have a guid.
I come from a microsoft sql background and in the ssms you can
choose type to "uniqeidentifier" and auto increment it.
In mysql however Ive found that you have to make triggers that execute on insert for the tables you want
to generate a guide id for. Example:
Table:
CREATE TABLE `tbl_test` (
`GUID` char(40) NOT NULL,
`Name` varchar(50) NOT NULL,
PRIMARY KEY (`GUID`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
Trigger:
CREATE TRIGGER `t_GUID` BEFORE INSERT ON `tbl_test`
FOR EACH ROW begin
SET new.GUID = uuid();
Alternatively you have to insert the guid yourself in the backend.
Im no DB expert but still remember that triggers cause performance problems.
The above is something I found here and is 9 years old so I was hoping something has changed?
As far as stated in the documentation, you can use uid() as a column default starting version 8.0.13, so something like this should work:
create table tbl_test (
guid binary(16) default (uuid_to_bin(uuid())) not null primary key,
name varchar(50) not null
);
This is pretty much copied from the documentation. I don't have a recent enough version of MySQL at hand to test this.
You can make a
INSERT INTO `tbl_test` VALUES (uuid(),'testname');
This would generate a new uuid, when you call it.
Or you can also use the modern uuid v4 by using one of these functions instead of the standard uuid(), which is more random than the uuid in mysql
How to generate a UUIDv4 in MySQL?
You can use since 8.0.13
CREATE TABLE t1 (
uuid_field VARCHAR(40) DEFAULT (uuid())
);
But you wanted more than unique, but here are only allowed internal functions and not user defined as for uuid v4, for that uyou need the trogger
As per the documentation, BINARY(x) adds some hidden padding bytes to the end of each entry, & VARCHAR(40) also wastes space by not being encoded directly in binary. Using VARBINARY(16) would be more efficient.
Also, more entropy (unguessability / security) per byte is available from RANDOM_BYTES(16) than standardized UUIDs, because they use some sections to encode constant metadata.
Perhaps the below will work for your needs.
-- example
CREATE TABLE `tbl_test` (
`GUID` VARBINARY(16) DEFAULT (RANDOM_BYTES(16)) NOT NULL PRIMARY KEY,
`Name` VARCHAR(50) NOT NULL
);
I've added some additional fields for my table in db. Now I need to have this additional fields in other few tables. So the question is - can I somehow copy those fields from source table and add them to another tables? Both mysql console and phpmyadmin variants woulbe be nice. Thanks!
A phpmyadmin variant would be to export the table's structure only (Export->Custom->Choose "Structure"). After that, you will get something like this in the exported SQL file:
CREATE TABLE `table` (
`id` int(10) NOT NULL,
`name` varchar(50) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
At that point, you can go ahead and remove the last line of the query and the parenthesis after the CREATE TABLE. Then, go ahead and substitute the [other_table] name and change the query to match the following:
ALTER TABLE `[other_table]`
ADD `id` int(10) NOT NULL,
ADD `name` varchar(50) DEFAULT NULL;
Notice how all I did was change CREATE to ALTER and add ADD before each field.
NOTE: This is not very useful on such a trivial example, but when dealing with large amounts of columns, it could prove somewhat useful.
I have created a MySQL table with the following code from a tutorial, I just put it into the MySQL console:
CREATE TABLE `test`.`name` (
`nameid` INT NOT NULL AUTO_INCREMENT ,
`firstname` VARCHAR(45) NULL ,
`lastname` VARCHAR(45) NULL ,
PRIMARY KEY (`nameid`)
);
INSERT INTO `test`.`name`
(`firstname`,`lastname`)
VALUES
("TheBig","Monster"),
("Guy","Smiley"),
("Big","Bird"),
("Oscar","Grouch"),
("Alastair","Cookie");
With the python script given in the tutorial I am able to print each item.
But when it comes to erase the table, I have tried all possible combinations of:
DROP TABLE `test`
DROP TABLE test
DROP TABLE `test`.`name`
etc, but none will erase it. Moreover, If I use the initial table creation script again, it will add the entries to the table, so I know its a stored table within MySQL but cannot access it, delete it, or list it with:
SHOW DATABASES
or
SHOW TABLES
It is my first afternoon with MySQL, but don't know how to go further if the commands in the MySQL help are not working!
So the summary question is:
How to delete / access the table created with the script?
drop table test.name;
this should work
I'm trying to import a SQL dump to another server. It fails on the first line. I'm first creating the exp_actions table and then inserting a bunch of data into it, but I get this really weird error.
SQL query:
--
-- Database: `ee_cmssite`
--
-- --------------------------------------------------------
--
-- Table structure for table `exp_actions`
--
CREATE TABLE `exp_actions` (
`action_id` INT( 4 ) UNSIGNED NOT NULL AUTO_INCREMENT ,
`class` VARCHAR( 50 ) NOT NULL DEFAULT '',
`method` VARCHAR( 50 ) NOT NULL DEFAULT '',
PRIMARY KEY ( `action_id` )
) ENGINE = MYISAM DEFAULT CHARSET = latin1 AUTO_INCREMENT =21;
MySQL said:
#1146 - Table 'site_ee.exp_actions' doesn't exist
Why doesn't it exist? I just instructed it to be created. I'm completely baffled. I've tried with and without IF_NOT_EXISTS
If anyone else comes across this seemingly bizarre error - see https://stackoverflow.com/a/11696069 for the solution.
I had the same symptoms and the cause was the same - moving to a new machine I took the old short-cut of simply copying the databases from the mysql/data directory that I needed directly into the new machine, however some were newer InnoDb types. This causes the Create Table throws table doesn't exist error. I had to drop the database and recreate it, then import from an sql dump.
According to the SQL script, the table exists in another database:
--
-- Database: ee_cmssite
-- --------------------------------------------------------
-- Table structure for table exp_actions
try to use ee_cmssite database instead.
While the error is not clear, I think this is related to the missing USE at the beginning of the file. mysqldump doesn't add a USE statement when you dump a single db. So you should add:
USE `ee_cmssite`;