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How to delete all records from table in sqlite with Android?
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You missed a space: db.execSQL("delete * from " + TABLE_NAME);
Also there is no need to even include *, the correct query is:
db.execSQL("delete from "+ TABLE_NAME);
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How to avoid mysql 'Deadlock found when trying to get lock; try restarting transaction'
I have a innoDB table which records online users. It gets updated on every page refresh by a user to keep track of which pages they are on and their last access date to the site. I then have a cron that runs every 15 minutes to DELETE old records.
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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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How to add 'ON DELETE CASCADE' in ALTER TABLE statement
I have a foreign key constraint in my table, I want to add ON DELETE CASCADE to it.
9 Answers
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How to find duplicates in 2 columns not 1
I have a MySQL database table with two columns that interest me. Individually they can each have duplicates, but they should never have a duplicate of BOTH of them having the same value.
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How can I add a column that doesn't allow nulls in a Postgresql database?
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You have to set a default value.
ALTER TABLE mytable ADD COLUMN mycolumn character varying(50) NOT NULL DEFAULT 'foo';
... some work (set real values as you want)...
ALTER TABLE mytable ALTER COLUMN mycolumn DROP DEFAULT;
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Make a DIV fill an entire table cell
...nswered) and we have CSS3! Is there any way to get a div to fill an entire table cell's width and height using CSS?
26 Answ...
What are the uses for Cross Join?
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size,
color
from
sizes CROSS JOIN colors
Maybe you want a table that contains a row for every minute in the day, and you want to use it to verify that a procedure has executed each minute, so you might cross three tables:
select
hour,
minute
from
hours CROSS JOIN minute...
Quickly reading very large tables as dataframes
I have very large tables (30 million rows) that I would like to load as a dataframes in R. read.table() has a lot of convenient features, but it seems like there is a lot of logic in the implementation that would slow things down. In my case, I am assuming I know the types of the columns ahead o...
Most efficient way to determine if a Lua table is empty (contains no entries)?
What's the most efficient way to determine if a table is empty (that is, currently contains neither array-style values nor dict-style values)?
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