I started learning SQL but just in my first query, failed, i was doing exactly the same as the mentor explaining in the course but somehow his code worked mine not.
I also tried this query on PopSql it also did not work.
What is wrong here?
You need to select the database you are running this query on.
To do this via MySQL Workbench:
Click on the 'Schemas' tab highlighted below:
Then double click on the name of the database you are trying to run the query on, the database name will be bolded once selected.
You need to tell MySQL which database to use:
USE database_name;
before you create a table.
In case the database does not exist, you need to create it as:
CREATE DATABASE database_name;
followed by:
USE database_name;
This involves MySQL 5.7 running on Windows Server 2016.
I'm working with a TRUNCATE statement in MySql to reduce the size of a large Log file (named "mySite.log"), which resides in:
ProgramData/MySQL/MySQL Server 5.7/Data/
I have researched and implemented the following:
mysql> SET GLOBAL general_log=OFF;
and this was successful.
However, I am trying to ascertain that the large log file that I see in the directory stated above is in fact the General Query Log File. It carries the name of the database as the prefix of the file name ("MySite.log") just as the other files (.bin's and .err, .pid) in the same directory do.
Is this large log file actually the general_log file? (If using MySQL Workbench, where would the naming of the log file and storage location be set up? I can't seem to locate that.)
Will the following syntax truncate the log file?
mysql> TRUNCATE TABLE mysql.general_log;
Will 'TRUNCATE TABLE' be used, even if the log is stored in a file, rather than database table?
Will 'mysql.general_log' need to be renamed to 'myDatabase.mysite' to match the name of my "MySite.log" file, from above?
Thanks for any leads.
Some interesting manual entries to read about this:
5.4.1 Selecting General Query and Slow Query Log Output Destinations
5.4.3 The General Query Log
You can check how your server is configured with
SHOW GLOBAL VARIABLES LIKE '%log%';
Then look for the value of log-output. This shows if you're logging to FILE, TABLE or both.
When it's FILE, check for the value of general_log_file. This is where the log file is in your file system. You can simply remove it, and create a new file (in case you ever want to enable general_log again). Then execute FLUSH LOGS; afterwards.
When it's TABLE then your TRUNCATE TABLE mysql.general_log; statement is correct.
Regarding your second question, just never mess with the tables in the mysql schema. Just don't (if you don't know what you're doing). Also I don't even get how you got to that thought.
After searching SO, I found answers to the following:
How to copy an entire MySQL schema using mysqldump
How to copy an entire MySQL schema using PHP
How to copy an entire MySQL schema using the enterprise edition of MySQL
How to copy an entire Microsoft SQL Server schema using the menus.
I also found a few hints about copying a MySQL schema using SQL commands.
My question: If I use the following SQL commands to copy a MySQL schema, what parts of the old schema would not be copied? Indexes? Constraints? Views? Anything else?
CREATE SCHEMA new_schema DEFAULT CHARACTER SET utf8;
CREATE TABLE new_schema.table1 LIKE old_schema.table1;
CREATE TABLE new_schema.table2 LIKE old_schema.table2;
CREATE TABLE new_schema.table3 LIKE old_schema.table3;
...;
INSERT INTO new_schema.table1 SELECT * FROM old_schema.table1;
INSERT INTO new_schema.table2 SELECT * FROM old_schema.table2;
INSERT INTO new_schema.table3 SELECT * FROM old_schema.table3;
...;
The CREATE TABLE ... LIKE will take care of indexes and constraints.
You should take care to SET FOREIGN_KEY_CHECKS=0 while you run this, because if table1 has a foreign key to table2, then creating table1 will fail. Likewise inserting data into the tables in the wrong order will fail.
Your script does not cover:
Views
Triggers
Stored procedures
Stored functions
Events
There are no CREATE... LIKE... statements for these other objects. You'll have to use SHOW CREATE... and then run it against in the context of the new schema. See the various SHOW CREATE... statements here: http://dev.mysql.com/doc/refman/5.6/en/show.html
I also caution that the way you INSERT INTO... SELECT FROM... will work, but can fill up your rollback segment if the table is very large. Tools like pt-archiver try to copy tables in batches, ascending along the primary key, to avoid this problem.
I think routines can't be copied directly with sql commands (as far as I know there's not such anything like create procedure myProc like old.myProc).
I would recommend you use mysqldump, since it takes care of copying everything, including the data (if you don't want to copy the data, you can use the -d switch to prevent creating the insert statements).
If you want to create a "template" (a database that is exactly like another database, but without the data), you can use the following:
mysqldump [connectionParameters] -d -R -v yourOldDatabase > databaseTemplate.sql
The options explained:
[connectionParameters]: host, user and password
-d: Don't copy data
-R: Include routines in the dump
-v: Output what mysqldump is doing to the console
You can open this "light" sql script to check how the objects were created.
Hope this helps
This question already has answers here:
How do I rename a MySQL database (change schema name)?
(46 answers)
Closed 9 days ago.
How can I change the database name of my database?
I tried to use the rename database command, but on the documents about it it is said that it is dangerous to use. Then what should I need to do to rename my database name?
For example, if I want to rename my database to this.
database1 -> database2?
Follow bellow steps:
shell> mysqldump -hlocalhost -uroot -p database1 > dump.sql
mysql> CREATE DATABASE database2;
shell> mysql -hlocalhost -uroot -p database2 < dump.sql
If you want to drop database1 otherwise leave it.
mysql> DROP DATABASE database1;
Note : shell> denote command prompt and mysql> denote mysql prompt.
I don't think it's possible.
You can use mysqldump to dump the data and then create a schema with your new name and then dump the data into that new database.
Unfortunately, MySQL does not explicitly support that (except for dumping and reloading database again).
From http://dev.mysql.com/doc/refman/5.1/en/rename-database.html:
13.1.32. RENAME DATABASE Syntax
RENAME {DATABASE | SCHEMA} db_name TO new_db_name;
This statement was added in MySQL 5.1.7 but was found to be dangerous and was removed in MySQL 5.1.23. ... Use of this statement could result in loss of database contents, which is why it was removed. Do not use RENAME DATABASE in earlier versions in which it is present.
"As long as two databases are on the same file system, you can use RENAME TABLE to move a table from one database to another"
-- ensure the char set and collate match the existing database.
SHOW VARIABLES LIKE 'character_set_database';
SHOW VARIABLES LIKE 'collation_database';
CREATE DATABASE `database2` DEFAULT CHARACTER SET = `utf8` DEFAULT COLLATE = `utf8_general_ci`;
RENAME TABLE `database1`.`table1` TO `database2`.`table1`;
RENAME TABLE `database1`.`table2` TO `database2`.`table2`;
RENAME TABLE `database1`.`table3` TO `database2`.`table3`;
http://dev.mysql.com/doc/refman/5.7/en/rename-table.html
You can change the database name using MySQL interface.
Go to http://www.hostname.com/phpmyadmin
Go to database which you want to rename. Next, go to the operation tab. There you will find the input field to rename the database.
InnoDB supports RENAME TABLE statement to move table from one database to another. To use it programmatically and rename database with large number of tables, I wrote a couple of procedures to get the job done.
You can check it out here - SQL script #Gist
To use it simply call the renameDatabase procedure.
CALL renameDatabase('old_name', 'new_name');
Tested on MariaDB and should work ideally on all RDBMS using InnoDB transactional engine.
I agree with above answers and tips but there is a way to change database name with phpmyadmin
Renaming the Database
From cPanel, click on phpMyAdmin. (It should open in a new tab.)
Click on the database you wish to rename in the left hand column.
Click on the Operations tab.
Where it says "Rename database to:" enter the new database name.
Click the Go button.
When it asks you to want to create the new database and drop the old database, click OK to proceed. (This is a good time to make sure you spelled the new name correctly.)
Once the operation is complete, click OK when asked if you want to reload the database.
here's the video tutorial:
http://support.hostgator.com/articles/specialized-help/technical/phpmyadmin/how-to-rename-a-database-in-phpmyadmin
Another way to rename the database or taking an image of the database is by using the reverse engineering option in the database tab. It will create an ER diagram for the database. Rename the schema there.
After that, go to the File menu and go to export and forward engineer the database.
Then you can import the database.
Sequel Ace database client have a rename database functionality. Select the database you would like to edit and click Database in the menu and then click Rename Database from the dropdown. Rename the database and ckick rename. Done!
After much aggravation this is what I have found to work"simply".
First thing, I am using MYSQL Workbench and the import would not work as it should, as the import dump file would always revert to the original schema name.
I spent several hours trying every thing to no avail,all for a spelling error.
I solved the issue by opening one of the .sql dump files in notebook and hand editing the typo's of the schema name, take care to rename all instances schema name has three in the beginning, save the file and then import. this worked perfectly for me and hope that it will help others looking for the simple answer to changing database names/schema names.
One more tip that I have found true, when programs do not do as they should go to the "source" literally find the source code.
Hope this helps someone
Low rep so they wont let me comment on the prior/post answer(it keeps changing rank or position), so I added it here. reverse engineering will work fine as long as there is no data in the sever table. if data exists and you try to update the server after the name change it will either pull an error or just create a new database/schema with no data, I know I tried ten times to no avail.
The above works simply and avoids headaches, as one can review the SQL code for other errors if any or change table names or creation data.
the .sql file is just a compiled SQL code so in theory one could copy and add it through PHP or the script console of the database management tool.
You can use below command
alter database Testing modify name=LearningSQL;
Old Database Name = Testing,
New Database Name = LearningSQL
Go to data directory and try this:
mv database1 database2
It works for me on a 900 MB database size.
Try:
RENAME database1 TO database2;
I've created and edited a couple of tables and don't want to recreate them from scratch if the database gets erased. What command allows me to "export" the field names and settings (NOT the content) as a ready to use MYSQL command that I can paste back on the MYSQL prompt?
SHOW CREATE TABLE tablename;
Reference: mySQL docs