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Table is marked as crashed and should be repaired
...an use the command (there must be ample space for the mysql files)
REPAIR TABLE `<table name>`;
for repairing individual tables
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jQuery delete all table rows except first
Using jQuery, how do I delete all rows in a table except the first? This is my first attempt at using index selectors. If I understand the examples correctly, the following should work:
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Can hash tables really be O(1)?
It seems to be common knowledge that hash tables can achieve O(1), but that has never made sense to me. Can someone please explain it? Here are two situations that come to mind:
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How do you delete a column by name in data.table?
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Any of the following will remove column foo from the data.table df3:
# Method 1 (and preferred as it takes 0.00s even on a 20GB data.table)
df3[,foo:=NULL]
df3[, c("foo","bar"):=NULL] # remove two columns
myVar = "foo"
df3[, (myVar):=NULL] # lookup myVar contents
# Method 2a ...
SQL Add foreign key to existing column
If I am using the following SQL command in SQL Server 2008 to update a table with a foreign key constraint:
6 Answers
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SQL WHERE ID IN (id1, id2, …, idn)
...DMS and so you would need us use @Ed Guiness's solution but here temporary tables do differ between RDBMS. (Effectively for complex problems you can't use just pure standard SQL)
– mmmmmm
Apr 27 '11 at 12:27
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How can I rename a database column in a Ruby on Rails migration?
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rename_column :table, :old_column, :new_column
You'll probably want to create a separate migration to do this. (Rename FixColumnName as you will.):
script/generate migration FixColumnName
# creates db/migrate/xxxxxxxxxx_fix_column_name....
Can I use a min-height for table, tr or td?
I am trying to show some details of a receive in a table.
7 Answers
7
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Does MySQL index foreign key columns automatically?
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Yes, but only on innodb. Innodb is currently the only shipped table format that has foreign keys implemented.
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How to delete a row by reference in data.table?
My question is related to assignment by reference versus copying in data.table . I want to know if one can delete rows by reference, similar to
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