How JPA (Hibernate) deal with transaction when fetching Object from database
By : Marcelus
Date : March 29 2020, 07:55 AM
Does that help There is no practical difference here, since you aren't changing any data. The query you execute will generate an SQL select. Transactions are there to allow you to apply ACID properties to a collection of inserts, updates, etc. However, if you begin manipulating the objects in the list returned from this method, calling setters, etc. those changes will be propagated back to the database out-with a transaction on an ad-hoc basis. In other words you'll effectively be working with the db in auto-commit mode. This is unlikely to be what you want.
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Parse background job query iterations are returning before fetching data
By : user3721536
Date : March 29 2020, 07:55 AM
like below fixes the issue Don't mix promises with callbacks, choose 1 of the 2 approaches and stick with it. Mixing and matching generally means something gets dropped and your function exits early without calling the status handler. Using promises will help you break the code up so its easier to follow. code :
query.find().then(function(x) {
... // basic logic
return object.save(); // return when creating a promise
}).then( function(y) {
...
}) ...
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Fetching data from multiple tables using transaction
By : adek ana
Date : March 29 2020, 07:55 AM
wish helps you You should do this with SQL INNER JOIN: code :
SELECT c.* , j.* FROM candidate AS c
INNER JOIN job AS j ON c.uniqid = j.candidate_uniqid
WHERE uniqid = @u
if (isset($_GET['uniqid'])) {
//if the uniqid is a number, use these two lines
$uniqid = intval($_GET['uniqid']);
mysqli_query($conn,"set @u = $uniqid");
//else, if the uniqid is a string, use these two lines
$uniqid = mysqli_real_escape_string($conn,$_GET['uniqid']);
mysqli_query($conn,"set @u = '$uniqid'");
$query = "SELECT c.* , j.* FROM candidate AS c
INNER JOIN job AS j ON c.uniqid = j.candidate_uniqid
WHERE uniqid = @u";
$result = mysqli_query($conn, $query);
while($row = mysqli_fetch_assoc($result)){
}
}
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Rollback transaction on pressing create button and fetching the value field to insert it into the form_for
By : Marno
Date : March 29 2020, 07:55 AM
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Fetching id field of an entity in the SQL Transaction
By : JJ Tang
Date : March 29 2020, 07:55 AM
help you fix your problem You can tell JDBC to return the generated ID from the insert statement, then you can use that ID to insert into the likes table: code :
mydb.prepareStatement(add_person_sql, new String[]{"pid"});
mydb.prepareStatement(add_person_sql, Statement.RETURN_GENERATED_KEYS);
add_person_statement.setString(1, pname);
add_person_statement.executeUpdate();
int newPid = -1;
ResultSet idResult = add_person.getGeneratedKeys();
if (idResult.next()) {
newPid = idResult.getInt(1);
}
add_likes_statement.setString(1, newPid);
add_likes_statement.setString(2, bid);
add_likes_statement.executeUpdate();
mydb.commit();
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