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Is an index needed for a primary key in SQLite?
When an integer column is marked as a primary key in an SQLite table, should an index be explicitly created for it as well? SQLite does not appear to automatically create an index for a primary key column, but perhaps it indexes it anyway, given its purpose? (I will be searching on that column all t...
Specify custom Date format for colClasses argument in read.table/read.csv
... way to specify the Date format when using the colClasses argument in read.table/read.csv?
4 Answers
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Vertically centering Bootstrap modal window
... </div>
</div>
CSS
.vertical-alignment-helper {
display:table;
height: 100%;
width: 100%;
pointer-events:none; /* This makes sure that we can still click outside of the modal to close it */
}
.vertical-align-center {
/* To center vertically */
display: table-ce...
How to do an INNER JOIN on multiple columns
...nds flights either by the city name or the airport code, but the flights table only contains the airport codes so if I want to search by city I have to join on the airports table.
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What's the difference between using INDEX vs KEY in MySQL?
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There's no difference. They are synonyms.
From the CREATE TABLE manual entry:
KEY is normally a synonym for INDEX. The key attribute PRIMARY KEY can
also be specified as just KEY when given in a column definition. This was
implemented for compatibility with other database sy...
How to filter SQL results in a has-many-through relation
Assuming I have the tables student , club , and student_club :
13 Answers
13
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How to wrap text using CSS? [duplicate]
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Try doing this. Works for IE8, FF3.6, Chrome
<body>
<table>
<tr>
<td>
<div style="word-wrap: break-word; width: 100px">gdfggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg...
Does a foreign key automatically create an index?
I've been told that if I foreign key two tables, that SQL Server will create something akin to an index in the child table. I have a hard time believing this to be true, but can't find much out there related specifically to this.
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Rails auto-assigning id that already exists
...to set the sequence for your company.id column to the highest value in the table with a query like this:
SELECT setval('company_id_seq', (SELECT max(id) FROM company));
I am guessing at your sequence name "company_id_seq", table name "company", and column name "id" ... please replace them with th...
In JavaScript, why is “0” equal to false, but when tested by 'if' it is not false by itself?
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Tables displaying the issue:
and ==
Moral of the story use ===
table generation credit: https://github.com/dorey/JavaScript-Equality-Table
sha...