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php is null or empty?
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As is shown in the following table, empty($foo) is equivalent to $foo==null and is_null($foo) has the same function of $foo===null. The table also shows some tricky values regarding the null comparison. (ϕ denotes an uninitialized variables. )
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Can I restore a single table from a full mysql mysqldump file?
I have a mysqldump backup of my mysql database consisting of all of our tables which is about 440 megs. I want to restore the contents of just one of the tables from the mysqldump. Is this possible? Theoretically, I could just cut out the section that rebuilds the table I want but I don't even know ...
How to center a checkbox in a table cell?
... contains nothing but a checkbox. It is rather wide because of text in the table header row. How do I center the checkbox (with inline CSS in my HTML? (I know))
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Show constraints on tables command
I have tables that I've tried setting PK FK relationships on but I want to verify this. How can I show the PK/FK restraints? I saw this manual page, but it does not show examples and my google search was fruitless also. My database is credentialing1 and my constrained tables are practices and ...
MySQL remove all whitespaces from the entire column
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To replace all spaces :
UPDATE `table` SET `col_name` = REPLACE(`col_name`, ' ', '')
To remove all tabs characters :
UPDATE `table` SET `col_name` = REPLACE(`col_name`, '\t', '' )
To remove all new line characters :
UPDATE `table` SET `col_name` = REP...
SQLite select where empty?
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It looks like you can simply do:
SELECT * FROM your_table WHERE some_column IS NULL OR some_column = '';
Test case:
CREATE TABLE your_table (id int, some_column varchar(10));
INSERT INTO your_table VALUES (1, NULL);
INSERT INTO your_table VALUES (2, '');
INSERT INTO your_t...
Cannot change column used in a foreign key constraint
I got this error when i was trying to alter my table.
3 Answers
3
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SQL error “ORA-01722: invalid number”
...er, and the string cannot be converted into a number.
Without seeing your table definition, it looks like you're trying to convert the numeric sequence at the end of your values list to a number, and the spaces that delimit it are throwing this error. But based on the information you've given us, ...
What is the advantage to using bloom filters?
...esenting sets, such as
self-balancing binary search trees,
tries, hash tables, or simple arrays
or linked lists of the entries. Most
of these require storing at least the
data items themselves, which can
require anywhere from a small number
of bits, for small integers, to an
arbitrar...
How to create ENUM type in SQLite?
I need to convert a table from MySQL to SQLite, but I can't figure out how to convert an enum field, because I can't find ENUM type in SQLite.
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