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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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CSS vertical alignment text inside li
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Define the parent with display: table and the element itself with vertical-align: middle and display: table-cell.
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How to get Last record from Sqlite?
I have a one table question_table and one ImageButton ( Back ). I need to get the last inserted record from the database after clicking on the Back .
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How do MySQL indexes work?
...ically, how can they return the data requested without scanning the entire table?
8 Answers
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How does a hash table work?
I'm looking for an explanation of how a hash table works - in plain English for a simpleton like me!
15 Answers
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How to Use slideDown (or show) function on a table row?
I'm trying to add a row to a table and have that row slide into view, however the slidedown function seems to be adding a display:block style to the table row which messes up the layout.
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Real life example, when to use OUTER / CROSS APPLY in SQL
...ORDER BY pr.name) pa
ORDER BY pr.name,
pa.name
2) Calling a Table Valued Function for each row in the outer query
SELECT *
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle)
3) Reusing a column alias
SELECT number,
doubled_number,
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SQL SELECT speed int vs varchar
I'm in the process of creating a table and it made me wonder.
9 Answers
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difference between primary key and unique key
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Primary Key:
There can only be one primary key in a table
In some DBMS it cannot be NULL - e.g. MySQL adds NOT NULL
Primary Key is a unique key identifier of the record
Unique Key:
Can be more than one unique key in one table
Unique key can have NULL values
It can be a can...
Ship an application with a database
...re database from there. This is much quicker if the database has a lot of tables and other components. Upgrades are triggered by changing the database version number in the res/values/strings.xml file. Upgrades would then be accomplished by creating a new database externally, replacing the old dat...