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What's the difference between identifying and non-identifying relationships?
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An identifying relationship is when the existence of a row in a child table depends on a row in a parent table. This may be confusing because it's common practice these days to create a pseudokey for a child table, but not make the foreign key to the parent part of the child's primary key. Fo...
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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How to center an element horizontally and vertically
...y/horizontally centered!</span>
</div>
Approach 3 - table-cell/vertical-align: middle:
Example Here / Full Screen Example
In some cases, you will need to ensure that the html/body element's height is set to 100%.
For vertical alignment, set the parent element's width/height...
中文网（自研/维护）拓展 · App Inventor 2 中文网
...otherwise.
DatabasePath()
Returns the path to the database.
Delete(table,whereClause,bindParams)
Executes a SQL DELETE statement.
DeleteAsync(tag,table,whereClause,bindParams)
Executes a SQL DELETE statement, asynchronously.
DeleteDatabase()
Delete the database.
Execute(sql,bi...
How to import multiple .csv files at once?
...r answers using things like do.call(rbind,...), dplyr::bind_rows() or data.table::rbindlist().
If you really want each data frame in a separate object, even though that's often inadvisable, you could do the following with assign:
temp = list.files(pattern="*.csv")
for (i in 1:length(temp)) assign(...
Simple basic explanation of a Distributed Hash Table (DHT)
...tore a particular key is found by hashing that key, so in effect your hash-table buckets are now independent nodes in a network.
This gives a lot of fault-tolerance and reliability, and possibly some performance benefit, but it also throws up a lot of headaches. For example, what happens when a nod...
How do I delete from multiple tables using INNER JOIN in SQL server
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You can take advantage of the "deleted" pseudo table in this example. Something like:
begin transaction;
declare @deletedIds table ( id int );
delete from t1
output deleted.id into @deletedIds
from table1 as t1
inner join table2 as t2
on t2.id = t...
Can a class member function template be virtual?
...teresting techniques stemming from combining polymorphism and templates, notably so-called type erasure.
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Form inside a table
I'm including some forms inside a HTML table to add new rows and update current rows. The problem that I'm getting is that when I inspect the forms in my dev tools, I see that the form elements are closed immediately after opening (inputs, etc are not included within the form).
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Naming of ID columns in database tables
I was wondering peoples opinions on the naming of ID columns in database tables.
24 Answers
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