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Questions - exists

Check if item already exists in cart when adding REACT

I have a cart. When adding a product it is having trouble for it to properly check if the same shoe and size already exists then to add it towards the quantity. For example Starting with an empty cart...
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pNut

reactjs

cart

exists

react-context

use-reducer

Votes: 0

Answers: 1

Latest Answer

I guess this could work: const existingProductIndex = state.cart.findIndex( ({ key, selectedSize }) => key === payload.key && selectedSize === payload.selectedSize ) if (!existingProdu...
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maxpsz

Android code is not finding the child in the Firebase database

I would like to take a variable in Android, loop through the Firebase database, and check if there is any child in Firebase that is equal to the variable. If it does not exist, prints that "The i...
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Carl

android

firebase

firebase-realtime-database

parent-child

exists

Votes: 0

Answers: 1

Latest Answer

I found the answer: public void onDataChange(@NonNull DataSnapshot dataSnapshot) { DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("Usuarios").child("5...
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Carl

scan does not delete expired keys in redis

I have some keys which have expiration in redis. I check them with EXISTS in my application and I decide based on its output. When they reach their expiration time, the TTL command, returns -1, but th...
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Zeinab Abbasimazar

redis

exists

ttl

Votes: 0

Answers: 1

Latest Answer

In Redis 2.6 or older the TTL command returns -1 if the key does not exist or if the key exists but has no associated expiration. Starting with Redis 2.8 the return value in case of an error changed: ...
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Ersoy

How to filter SQL results when the referenced table can be empty?

I have a query which selects from different tables, then uses a WHERE clause to filter the items. The clause looks like this: WHERE allItems.NumID != (SELECT RelatedNumID FROM allRelated WHERE NumID =...
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user3132457

sql

sqlite

left-join

where-clause

exists

Votes: 0

Answers: 1

Latest Answer

Try with NOT EXISTS: WHERE NOT EXISTS ( SELECT 1 FROM allRelated WHERE allRelated.NumID = allItems.NumID AND allRelated.RelatedNumID = allItems.NumID ) or, change the condition in the WH...
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forpas

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