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sql primary key and index
...ed in PRIMARY KEY, but allowed in UNIQUE index; and like in set operators (UNION, EXCEPT, INTERSECT), here NULL = NULL which means that you can have only one value as two NULLs are find as duplicates of each other;
only one PRIMARY KEY may exists per table while 999 unique indexes can be created
whe...
How do you track record relations in NoSQL?
... not need A and you have less than Peta bytes just leave it, go ahead with MySql or Postgres.
good luck
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How to store decimal values in SQL Server?
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In MySQL DB decimal(4,2) allows entering only a total of 4 digits. As you see in decimal(4,2), it means you can enter a total of 4 digits out of which two digits are meant for keeping after the decimal point.
So, if you enter 1...
AJAX POST and Plus Sign ( + ) — How to Encode?
... and the plus sign (+) when i to try to save javascript "code examples" to mysql:
my solution (not the better way, but it works):
javascript:
function replaceAll( text, busca, reemplaza ){
while (text.toString().indexOf(busca) != -1)
text = text.toString().replace(busca,reemplaza);return text...
How do you find the disk size of a Postgres / PostgreSQL table and its indexes
... where table_schema = 'public' and table_type = 'BASE TABLE'
union
-- materialized views
SELECT oid::regclass::text as table_name
FROM pg_class
WHERE relkind = 'm'
order by table_name
) AS all_tables
-- ORDER BY total_size DESC
order ...
How can I get column names from a table in SQL Server?
...ry to get column name and all details without using
INFORMATION_SCHEMA in MySql :
SHOW COLUMNS FROM database_Name.table_name;
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SELECT INTO a table variable in T-SQL
...ce table as long as the CTE doesn't reference multiple tables using joins, unions , etc.
– nanestev
Apr 13 '18 at 14:11
2
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房多多：懂用户比懂互联网重要 - 资讯 - 清泛网 - 专注C/C++及内核技术
...我们到底应该给用户带来什么，让我们的效率提高，或者如何让整个行业的交易成本降低，我想现在所有的认知都会成为未来生存的障碍。
要改造他们、为他们植入移动互联网的基因，这样才能提高整个内部的效率，进而打造...
Multi-line strings in PHP
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You forgot if I have loops or MySQL while loops between. Thanks
– TheBlackBenzKid
Mar 16 '12 at 20:40
93
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Commenting code in Notepad++
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From dev.mysql.com - From a “-- ” sequence to the end of the line. In MySQL, the “-- ” (double-dash) comment style requires the second dash to be followed by at least one whitespace or control character (such as a space, tab, ...