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MySQL error: key specification without a key length
I have a table with a primary key that is a varchar(255). Some cases have arisen where 255 characters isn't enough. I tried changing the field to a text, but I get the following error:
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Populating a database in a Laravel migration file
... just learning Laravel, and have a working migration file creating a users table. I am trying to populate a user record as part of the migration:
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Store query result in a variable using in PL/pgSQL
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I think you're looking for SELECT INTO:
select test_table.name into name from test_table where id = x;
That will pull the name from test_table where id is your function's argument and leave it in the name variable. Don't leave out the table name prefix on test_table.name or ...
Adding an identity to an existing column
I need to change the primary key of a table to an identity column, and there's already a number of rows in table.
19 Answe...
How to convert an entire MySQL database characterset and collation to UTF-8?
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Use the ALTER DATABASE and ALTER TABLE commands.
ALTER DATABASE databasename CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
ALTER TABLE tablename CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
Or if you're still on MySQL 5.5.2 or older wh...
How to check if a table contains an element in Lua?
Is there a method for checking if a table contains a value ? I have my own (naive) function, but I was wondering if something "official" exists for that ? Or something more efficient...
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SQLite Reset Primary Key Field
I have a few tables in SQLite and I am trying to figure out how to reset the auto-incremented database field.
4 Answers
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ALTER TABLE without locking the table?
When doing an ALTER TABLE statement in MySQL, the whole table is read-locked (allowing concurrent reads, but prohibiting concurrent writes) for the duration of the statement. If it's a big table, INSERT or UPDATE statements could be blocked for a looooong time. Is there a way to do a "hot alter", li...
How can I get column names from a table in Oracle?
...he database to get the column names , not to be confused with data in the table. For example, if I have a table named EVENT_LOG that contains eventID , eventType , eventDesc , and eventTime , then I would want to retrieve those field names from the query and nothing else.
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How to truncate a foreign key constrained table?
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You cannot TRUNCATE a table that has FK constraints applied on it (TRUNCATE is not the same as DELETE).
To work around this, use either of these solutions. Both present risks of damaging the data integrity.
Option 1:
Remove constraints
Perform...