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Computed / calculated / virtual / derived columns in PostgreSQL
...enerated columns are introduced with Postgres 12. Trivial example:
CREATE TABLE tbl (
int1 int
, int2 int
, product bigint GENERATED ALWAYS AS (int1 * int2) STORED
);
db<>fiddle here
VIRTUAL generated columns may come with one of the next iterations. (Not in Postgres 13, yet) .
...
Postgres and Indexes on Foreign Keys and Primary Keys
...ys? How can I tell? Is there a command that will return all indexes on a table?
7 Answers
...
Why not use tables for layout in HTML? [closed]
It seems to be the general opinion that tables should not be used for layout in HTML.
66 Answers
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ERROR: Error 1005: Can't create table (errno: 121)
... constraints use the following SQL query:
SELECT
constraint_name,
table_name
FROM
information_schema.table_constraints
WHERE
constraint_type = 'FOREIGN KEY'
AND table_schema = DATABASE()
ORDER BY
constraint_name;
Look for more information there, or try to see where the error o...
Add a column to a table, if it does not already exist
I want to write a query for MS SQL Server that adds a column into a table. But I don't want any error display, when I run/execute the following query.
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Improving bulk insert performance in Entity framework [duplicate]
I want to insert 20000 records in a table by entity framework and it takes about 2 min. Is there any way other than using SP to improve its performance. This is my code:
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Add column to SQL Server
I need to add a column to my SQL Server table. Is it possible to do so without losing the data, I already have?
5 Answers...
Make a DIV fill an entire table cell
...nswered) and we have CSS3! Is there any way to get a div to fill an entire table cell's width and height using CSS?
26 Answ...
What is InnoDB and MyISAM in MySQL?
...er on their locking implementation: InnoDB locks the particular row in the table, and MyISAM locks the entire MySQL table.
You can specify the type by giving MYISAM OR InnoDB while creating a table in DB.
share
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Is there a naming convention for MySQL?
... this is not always possible. Think about how you would cope with a single table foo_bar that has columns foo_id and another_foo_id both of which reference the foo table foo_id column. You might want to consider how to deal with this. This is a bit of a corner case though!
Point 4 - Similar to Poin...