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Postgres: How to do Composite keys?
... error, and omit the redundant CONSTRAINT (already implied), too:
CREATE TABLE tags
(
question_id INTEGER NOT NULL,
tag_id SERIAL NOT NULL,
tag1 VARCHAR(20),
tag2 VARCHAR(20),
tag3 VARCHAR(20),
PRIMARY ...
How do you use script variables in psql?
...nd can then be substituted, for example, as ...
SELECT * FROM :myvariable.table1;
... or ...
SELECT * FROM table1 WHERE :myvariable IS NULL;
edit: As of psql 9.1, variables can be expanded in quotes as in:
\set myvariable value
SELECT * FROM table1 WHERE column1 = :'myvariable';
In olde...
How do you debug MySQL stored procedures?
...current process for debugging stored procedures is very simple. I create a table called "debug" where I insert variable values from the stored procedure as it runs. This allows me to see the value of any variable at a given point in the script, but is there a better way to debug MySQL stored procedu...
What are the possible values of the Hibernate hbm2ddl.auto configuration and what do they do
...this option is used it does not drop the whole schema instead it drops the tables whose mappings are available while running this. For example if a database with Schema S has A, B, C tables and java code has mappings for A and B only then Hibernate will not drop the table C.
– ...
Cloning a MySQL database on the same MySql instance
... you... There's no way to do this within MySQL afaik (except by hand, one table / view at a time)
– Greg
Mar 23 '09 at 21:50
42
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Delete all Duplicate Rows except for One in MySQL? [duplicate]
How would I delete all duplicate data from a MySQL Table?
2 Answers
2
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Assign multiple columns using := in data.table, by group
What is the best way to assign to multiple columns using data.table ? For example:
2 Answers
...
User recognition without cookies or local storage
... $totalRun = 0;
$yin = 0;
// Trains RNA until it gets stable
while ($keepTrainning == true) {
// Sweeps each row of the input subject
foreach ($input as $row_counter => $row_data) {
// Finds out the number of columns the input ha...
Create unique constraint with null columns
I have a table with this layout:
4 Answers
4
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Generate GUID in MySQL for existing Data?
I've just imported a bunch of data to a MySQL table and I have a column "GUID" that I want to basically fill down all existing rows with new and unique random GUID's.
...