I have 3 tables TAble, TableB and TableC.
each one with 1 milion registers.
And i have the Laravel eloquent query.
$list= TableA::with([
'TableB',
'TableC'
])
->whereIn('field1',['A','B','C'])
->where('created_at','>=','2018-01-01') ->orderBy('fieldC', 'ASC')->orderBy('created_at', 'ASC')
->get()
->take(50) ;
TableA have TableB and TableC mapping this way.
public function TableB(){
return $this->belongsTo('TableB', 'fk_id', 'id');
}
public function TableC(){
return $this->hasMany('TableC');
}
How can i execute this query limiting number of registes in "TableB" and "TableC".
if i use take() it only limits the final result.
What do you want to do?
If you want to process data in chunks use
->chunk(50, function ($data) use ($variable) {
//process
});
If you want display data in tables with pages use paginate.
Related
return $this->hasMany(Key::class, 'order_id' , 'order_id')->with('supplier');
How can I add a 2nd condition here, both order_id must be equal to order_id and game_id must be equal to game_id.
I think you can use this way to have multiple conditions
public function whatever()
{
return Whatever::where(function ($query) {
return $query->where('order_id', $this->order_id)
->where('game_id', $this->game_id);
});
}
I have 3 columns in my database. 2 columns is connected with one column by using a hybrid relationship.
here is my query.
$data=Client::with('product','department')->select(['product.product_name','product.product_description']);
how to select row from another table?
in your product or department relation method do the selection with all the forging keys if you have any other relation for product for later use is you want them like
public function product()
{
return $this->hasMany(department::class)->select(['id', 'another_relation_to_product_id', 'product_name', 'product_description']);
}
You can do it this way
$data = Client::with(['product:id,product_name,product_description','department'])->get();
see docs https://laravel.com/docs/5.7/eloquent-relationships#constraining-eager-loads in Eager Loading Specific Columns section. Or you can do it
App\User::with([
'product' => function ($query) {
$query->select('id', 'product_name', 'product_description');
},
'department'
])->get();
I am learning how to do simple queries using the Yii2 framework. I use PostgreSQL.
I am trying to join two tables and get the data from both tables with a where condition.
The tables are called Admins and Persons.
The join use field called idadm.
The condition is idadm = 33. This works great but the result has data only from the Admins table and I need data from the other table.
Here is my example:
$query = \app\models\Admins::find()
->select('*')
->leftJoin('persons', 'persons.idadm = admins.idadm')
->where(['admins.idadm' => 33])
->with('persons')
->all();
I am following the Yii2 official guide: http://www.yiiframework.com/doc-2.0/guide-db-active-record.html
Update: Here I show the updated code that doesn't solve de problem:
You need to write all column name in select().
$query = \app\models\Admins::find()
->select('admin.*,persons.*') // make sure same column name not there in both table
->leftJoin('persons', 'persons.idadm = admins.idadm')
->where(['admins.idadm' => 33])
->with('persons')
->all();
And also you need to define person table attributes in Admin model.
Second way is get records as array,so you dont need to define attributes in Admin model.
$query = \app\models\Admins::find()
->select('admin.*,persons.*') // make sure same column name not there in both table
->leftJoin('persons', 'persons.idadm = admins.idadm')
->where(['admins.idadm' => 33])
->with('persons')
->asArray()
->all();
Ensure that active record has required relations, e.g. something like follows:
class Admins extends \yii\db\ActiveRecord {
public function table() {
return "admins";
}
public function getPersons()
{
return $this->hasMany(Person::className(), ['idadm' => 'idadm']);
}
}
class Person extends \yii\db\ActiveRecord {
public function table() {
return "persons";
}
}
Then use joinWith to build query:
$query = Admins::find()
->joinWith('persons')
->limit(1);
$result = $query->createCommand()->getSql();
echo $result;
Here is produced query:
SELECT `admins`.* FROM `admins`
LEFT JOIN `person` ON `admins`.`idadm` = `person`.`idadm` LIMIT 1
Following is the code which is blowing up if the list which is being passed in to "IN" clause has several values. In my case the count is 1400 values. Also the customer table has several thousands (arround 100,000) of records in it. The query is executing against DERBY database.
public List<Customer> getCustomersNotIn(String custType, List<Int> customersIDs) {
TypedQuery<Customer> query = em.createQuery("from Customer where type=:custType and customerId not in (:customersIDs)", Customer.class);
query.setParameter("custType", custType);
query.setParameter("customersIDs", customersIDs);
List<Customer> customerList = query.getResultList();
return customerList;
}
The above mentioned method perfectly executes if the list has less values ( probably less than 1000 ), if the list customersIDs has more values since the in clause executes based on it, it throws an error saying "Statement too complex"
Since i am new to JPA can any one please tell me how to write the above mention function in the way described below.. * PLEASE READ COMMENTS IN CODE *
public List<Customer> getCustomersNotIn(String custType, List<Int> customersIDs) {
// CREATE A IN-MEMORY TEMP TABLE HERE...
// INSERT ALL VALUES FROM customerIDs collection into temp table
// Change following query to get all customers EXCEPT THOSE IN TEMP TABLE
TypedQuery<Customer> query = em.createQuery("from Customer where type=:custType and customerId not in (:customersIDs)", Customer.class);
query.setParameter("custType", custType);
query.setParameter("customersIDs", customersIDs);
List<Customer> customerList = query.getResultList();
// REMOVE THE TEMP TABLE FROM MEMORY
return customerList;
}
The Derby IN clause support does have a limit on the number of values that can be supplied in the IN clause.
The limit is related to an underlying limitation in the size of a single function in the Java bytecode format; Derby currently implements IN clause execution by generating Java bytecode to evaluate the IN clause, and if the generated bytecode would exceed the JVM's basic limitations, Derby throws the "statement too complex" error.
There have been discussions about ways to fix this, for example see:
DERBY-6784
DERBY-6301, or
DERBY-216
But for now, your best approach is probably to find a way to express your query without generating such a large and complex IN clause.
Ok here is my solution that worked for me. I could not change the part generating the customerList since it is not possible for me, so the solution has to be from within this method. Bryan your explination was the best one, i am still confuse how "in" clause worked perfectly with table. Please see below solution.
public List<Customer> getCustomersNotIn(String custType, List<Int> customersIDs) {
// INSERT customerIds INTO TEMP TABLE
storeCustomerIdsIntoTempTable(customersIDs)
// I AM NOT SURE HOW BUT, "not in" CLAUSE WORKED INCASE OF TABLE BUT DID'T WORK WHILE PASSING LIST VALUES.
TypedQuery<Customer> query = em.createQuery("select c from Customer c where c.customerType=:custType and c.customerId not in (select customerId from TempCustomer)");
query.setParameter("custType", custType);
List<Customer> customerList = query.getResultList();
// REMOVE THE DATA FROM TEMP TABLE
deleteCustomerIdsFromTempTable()
return customerList;
}
private void storeCustomerIdsIntoTempTable(List<Int> customersIDs){
// I ENDED UP CREATING TEMP PHYSICAL TABLE, INSTEAD OF JUST IN MEMORY TABLE
TempCustomer tempCustomer = null;
try{
tempCustomerDao.deleteAll();
for (Int customerId : customersIDs) {
tempCustomer = new TempCustomer();
tempCustomer.customerId=customerId;
tempCustomerDao.save(tempCustomer);
}
}catch(Exception e){
// Do logging here
}
}
private void deleteCustomerIdsFromTempTable(){
try{
// Delete all data from TempCustomer table to start fresh
int deletedCount= tempCustomerDao.deleteAll();
LOGGER.debug("{} customers deleted from temp table", deletedCount);
}catch(Exception e){
// Do logging here
}
}
JPA and the underlying Hibernate simply translate it into a normal JDBC-understood query. You wouldn't write a query with 1400 elements in the IN clause manually, would you? There is no magic. Whatever doesn't work in normal SQL, wouldn't in JPQL.
I am not sure how you get that list (most likely from another query) before you call that method. Your best option would be joining those tables on the criteria used to get those IDs. Generally you want to execute correlated filters like that in one query/transaction which means one method instead of passing long lists around.
I also noticed your customerId is double - a poor choice for a PK. Typically people use long (autoincremented/sequenced, etc.) And I don't get the "temp table" logic.
i know i can define relationships through _referenceMap, i know that i con join selects trough
$db->select()
But what i need is to fetch rowset in model extending Zend_Db_Table_Abstract and then order it by value of referenced column from another table.
Is there some workaround to do that?
edit:
heres is the example:
first table:
table bugs columns id, bugname, authorid
second table:
table authors columns id, authorname
I have a model Model_Bugs extends Zend_Db_Table_Abstract
I want to make something like this:
$model->fetchAll($model->select()->order('authorname ASC'))
This means, that i need to join tables and sort by a column, which is not in the model table.
thanks for help
Jan
I would add a method in Model_Bugs like so:
public function fetchBugsByAuthorname() {
$bugTable = $this;
$bugTableName = $this->info('name');
$authorsTable = new Model_Authors();
$authorsTableName = $authorsTable->info('name');
$select = $bugTable->select()
->setIntegrityCheck(false)
->from($bugTable, array('id', 'bugname', 'authorid'))
->join($authorsTableName,
"$bugTableName.authorid = $authorsTableName.id",
array("authorname"))
->order("$authorsTableName.authorname asc");
$result = $bugTable->fetchAll($select);
return $result;
}
But to do this you have to turn off ZF's table integrity checking (setIntegrityCheck(false) above), which means you won't be able to directly call save() on the resulting rows. But if it's for a read-only purpose, it will work.
If you needed to save rowsets back to the database, you may have to first select the author ID's from Model_Authors in the order you want them, and then re-order your Model_Bugs query accordingly. It's messier but it can work.