In the documentation, it is said:
Table and database names are stored on disk using the lettercase
specified in the CREATE TABLE or CREATE DATABASE statement.
I Googled a lot to know how to use "lettercase" in a specific CREATE DATABASE statement but didn't find it.
Table and Database names case sensitivity depends on system where MySQL is running. Names are stored in separated file names. So for example file names on windows are not case sensitive but on linux file names are case sensitive.
Linux
Table and Database names are case sensitive
Windows
Table and Database names are case insensitive
it means that table and database names are cAsESeNsItIvE
Related
I want to name my mysql table column names using camel case and create php classes from these mysql tables with the same camel case names. I will be generating these php classes automatically. I'm wondering if I can rely on column name case no matter what platform I run my application on. So for example, if I name one column name "FirstName", will I ever encounter a time where reading the column name from the database will product "firstname" or something like that?
Short answer is no.
The long answer is that case-sensitivity for some things in MySQL depend on the underlying operating system. (Unix being the sensitive one)
Here is the reference to the issue in the MySQL documentation.
Consequently, the case sensitivity of the underlying operating system plays a part in the case sensitivity of database and table names. This means database and table names are not case sensitive in Windows, and case sensitive in most varieties of Unix. One notable exception is Mac OS X, which is Unix-based but uses a default file system type (HFS+) that is not case sensitive.
Also from the documentation on column names specifically:
Column, index, and stored routine names are not case sensitive on any platform, nor are column aliases. Trigger names are case sensitive, which differs from standard SQL.
MySQL is case sensitive in table and column names, and case in-sensitive in keywords.
But note that Windows is only case preserving, and file names are table names. (If you work on table "SalesAccounts" when you meant "Salesaccounts" then it will read OK on Windows and fail on Linux.
You should be OK with what you want to do, but
1) Test on Linux,
2) Test the tools you are using.
I'm currently moving my project to production and found an odd situation. The database was (unfortunately) created with object names in lowercase. Now, I'm acting on table all over my 100+ stored procedures/functions, not always keeping in mind the fact that I should use lowercase for table names.
I made a simple test:
select * from mytable ;
yields all the records in the table, whereas:
select * from Mytable ;
returns a "table does not exist" error.
Is there any solution someone could suggest besides going one by one through each and every stored procedure/function and correct the case of the table names?
Thanking in advance for any life-saving suggestion.
From the MySQL documentation on cases in identifiers:
In MySQL, databases correspond to directories within the data
directory. Each table within a database corresponds to at least one
file within the database directory (and possibly more, depending on
the storage engine). Triggers also correspond to files. Consequently,
the case sensitivity of the underlying operating system plays a part
in the case sensitivity of database, table, and trigger names.
I would probably take the time to make everything lower case because it will save you headaches further down the line. If you have a client with a decent editor like MySQL Workbench then you can do these replaces with a quick find and replace.
EDIT:
According to the documentation, you can try setting the lower_case_table_names system variable to 1, which will:
Table names are stored in lowercase on disk and name comparisons are
not case sensitive. MySQL converts all table names to lowercase on
storage and lookup. This behavior also applies to database names and
table aliases.
This might solve your problem if all of the table had been created with lowercase on disk.
Does anyone know HOW I might preserve case in my table names please
(Win 10 using phpMyAdmin,latest xampp distribution). Could this be because xampp is using MariaDB instead of mySQL?
Table names being rewritten to all lowercase.
Read on phpMyAdmin site that to use preserve case I should add:
'set-variable=lower_case_table_names=0'
this stopped mySQL starting with an error message:
[ERROR] c:\xampp\mysql\bin\mysqld.exe: unknown variable 'set-variable=lower_case_table_names=0'
Then after reading an answer here I learned I should use lower_case_table_names=0so aded that to my.ini and still got the same error.
I then spent 20 mins trying to work out where my set-variable=lower_case_table_names=0 was set. (Thought it must be cached or duplicated or something.)
In desperation I deleted the lower_case_table_names=0 and the error disappeared. I put it back and got the
[ERROR] c:\xampp\mysql\bin\mysqld.exe: unknown variable 'set-variable=lower_case_table_names=0' error. IE they seem to be aliases with the error reporting translating. Somewhat irritating.
You should read the documentation bit more carefully, specifically identifier case sensitivity section.
In MySQL, databases correspond to directories within the data
directory. Each table within a database corresponds to at least one
file within the database directory (and possibly more, depending on
the storage engine). Triggers also correspond to files. Consequently,
the case sensitivity of the underlying operating system plays a part
in the case sensitivity of database, table, and trigger names. This
means such names are not case sensitive in Windows, but are case
sensitive in most varieties of Unix.
Value Meaning
0 Table and database names are stored on disk using the
lettercase specified in the CREATE TABLE or CREATE DATABASE statement.
Name comparisons are case sensitive. You should not set this
variable to 0 if you are running MySQL on a system that has
case-insensitive file names (such as Windows or OS X). If you force
this variable to 0 with --lower-case-table-names=0 on a
case-insensitive file system and access MyISAM tablenames using
different lettercases, index corruption may result. 1 Table names are
stored in lowercase on disk and name comparisons are not case
sensitive. MySQL converts all table names to lowercase on storage and
lookup. This behavior also applies to database names and table
aliases. 2 Table and database names are stored on disk using the
lettercase specified in the CREATE TABLE or CREATE DATABASE statement,
but MySQL converts them to lowercase on lookup. Name comparisons are
not case sensitive. This works only on file systems that are not case
sensitive! InnoDB table names are stored in lowercase, as for
lower_case_table_names=1.
To summarise: on windows you should not set lower_case_table_names to 0. If you want to preserve the letter case for table names on windows, then set lower_case_table_names to 2.
The using system variables section explains how to set a system variable in various ways.
Putting lower_case_table_names=2 in your my.ini files allows the use of upper and lower case in tabel names... BUT .... BIG BUT... it does NOT allow you to put upper case letters into EXISTING file names.
The solution is to COPY your table to a new table with the "correct" name.
However as this only changes the appearance of the table names (tables are stored in lower case files) you must use an intermediate table.
EG you want the table name to be HelloWorld but you discover it is stored as helloworld. Add the line above to your my.ini file then make a copy helloworld to a new table, say "helloTemp", delete helloworld copy helloTemp to HelloWorld delete helloTemp and you have a table with HelloWorld as the name.
In Linux server I am Configure Apache and PhpMyadmin.
In the database my table's name is mst_vehicle
when I fire a query like select * from mst_vehicle it will give right result, but
When I fire a query like select * from Mst_Vehicle It will give an error.
Please help me how to resolve this problem.
I import the database from windows to linux phpmyadmin and my windows database is already with lower case table name.
Database and table names are not case sensitive in Windows, and case sensitive in most varieties of Unix.
In MySQL, databases correspond to directories within the data
directory. Each table within a database corresponds to at least one
file within the database directory (and possibly more, depending on
the storage engine). Consequently, the case sensitivity of the
underlying operating system plays a part in the case sensitivity of
database and table names. This means database and table names are not
case sensitive in Windows, and case sensitive in most varieties of
Unix. One notable exception is Mac OS X, which is Unix-based but uses
a default file system type (HFS+) that is not case sensitive.
Have a look at Identifier Case Sensitivity.
You can get the correct case-sensitive table name from case-ignorant name by doing this:
select table_name from information_schema.tables where lower(table_name)="mst_vehicle" and table_schema="YourDatabaseName"
It will however add a performance penalty.
I have a a problem whereby my production server runs Unix and my dev server runs MS Windows.
The problem is that Windows is not case sensitive and Unix is. So my table set on the production server uses Uppercase table names ie "Customers" and on Windows the table names are in lowercase "customers".
All this is fine until you need to get data from one box to another and your SQL export says insert into "customers" in lowercase, and presto "Unkown table customers". Because the production server is currently on a shared hosting plan i cant change the settings and install the key that ignores case.
So my question, is there a way to get Windows to convert the tables back to the correct case or is there some setting I can include in the export SQL file so that i can upload data without this problem.
Thanks
UPDATE
Here is what I discovered for anybody else having this issue.
If you have already set up your tables running MySQL on Windows adding
lower_case_table_names=2 to your my.cnf or my.ini file will not change the case of your tables automatically even if they were originally created using uppercase or mixed case names.
CREATE TABLE "MyTable" will create a new table "mytable" not "MyTable" even when lower_case_table_names=2 is set in your my.cnf file.
To get around this problem use this method
Make a copy of your original table
Drop your original table
Rename your copy table using the correct case.
This is the only way it will work. Hope this helps somebody.
Taken from dev.mysql.com:
To avoid data transfer problems arising from lettercase of database or table names, you have two options:
Use lower_case_table_names=1 on all systems. The main disadvantage with this is that when you use SHOW TABLES or SHOW DATABASES, you do not see the names in their original lettercase.
Use lower_case_table_names=0 on Unix and lower_case_table_names=2 on Windows. This preserves the lettercase of database and table names. The disadvantage of this is that you must ensure that your statements always refer to your database and table names with the correct lettercase on Windows. If you transfer your statements to Unix, where lettercase is significant, they do not work if the lettercase is incorrect.
Exception: If you are using InnoDB tables and you are trying to avoid these data transfer problems, you should set lower_case_table_names to 1 on all platforms to force names to be converted to lowercase.
If you plan to set the lower_case_table_names system variable to 1 on Unix, you must first convert your old database and table names to lowercase before stopping mysqld and restarting it with the new variable setting.
There is one easy solution:
Always name your tablenames lowercase.
The universal guiding philosophy of Windows with respect to case is "case-insensitive, case stored". That means Windows never intends to discard your case, so it's a little mysterious why your tables on Windows are lower-case.
Apologies if this is a dumb question, but have you tried renaming the tables on the Windows machine so they have the correct case pattern?