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SQL Server Profiler - How to filter trace to only display events from one database?
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Under Trace properties > Events Selection tab > select show all columns. Now under column filters, you should see the database name. Enter the database name for the Like section and you should see traces only for that database.
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List of foreign keys and the tables they reference
..._name of the table ALL_CONSTRAINTS. This will give you the info you want:
SELECT a.table_name, a.column_name, a.constraint_name, c.owner,
-- referenced pk
c.r_owner, c_pk.table_name r_table_name, c_pk.constraint_name r_pk
FROM all_cons_columns a
JOIN all_constraints c ON a.owner ...
How to force LINQ Sum() to return 0 while source collection is empty
...word
&& l.Property.PropertyId == PropertyId)
.Select(l => l.Amount)
.DefaultIfEmpty(0)
.Sum();
This way, your query will only select the Amount field. If the collection is empty, it will return one element with the value of 0 and then the sum will ...
How do I configure a Python interpreter in IntelliJ IDEA with the PyCharm plugin?
... to File > Project Structure.
Under the Project menu for Project SDK, select "New" and
Select "Python SDK", then select "Local".
Provided you have a Python SDK installed, the flow should be natural from there - navigate to the location your Python installation lives.
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How do MySQL indexes work?
...be faster to go through the pages one by one (in a database, this is "poor selectivity").
For a 10-page book, it makes no sense to make an index, as you may end up with a 10-page book prefixed by a 5-page index, which is just silly - just scan the 10 pages and be done with it.
The index also needs t...
Joining three tables using MySQL
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Simply use:
select s.name "Student", c.name "Course"
from student s, bridge b, course c
where b.sid = s.sid and b.cid = c.cid
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Join between tables in two different databases?
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Yes, assuming the account has appropriate permissions you can use:
SELECT <...>
FROM A.table1 t1 JOIN B.table2 t2 ON t2.column2 = t1.column1;
You just need to prefix the table reference with the name of the database it resides in.
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Why can't radio buttons be “readonly”?
...ton by disabling only the un-checked radio buttons. It keeps the user from selecting a different value, and the checked value will always post on submit.
Using jQuery to make readonly:
$(':radio:not(:checked)').attr('disabled', true);
This approach also worked for making a select list readonly, ...
SQL UPDATE SET one column to be equal to a value in a related table referenced by a different column
...result set to update is before running the update (same query, just with a select):
select *
from QuestionTrackings q
inner join QuestionAnswers a
on q.AnswerID = a.AnswerID
where q.QuestionID is null -- and other conditions you might want
Particularly whether each answer id has definitely only 1...
Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails
... have to get rid of those first.
Here's a query that can find those IDs:
SELECT DISTINCT sourcecode_id FROM
sourcecodes_tags tags LEFT JOIN sourcecodes sc ON tags.sourcecode_id=sc.id
WHERE sc.id IS NULL;
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