I am trying to verify whether the parent element has a unique child element by element name.
I also need to verify that there is at least one possible element.
Example
It will work but
Tag: Unique
One article reads the distributed unique ID generation
Many large Internet companies have a large amount of data, and they all use sub-databases and tables, so after sub-databases, a unified unique ID is required for storage. This ID can be in incremen
Research distributed unique ID generation, after reading this article
Many large Internet companies have a large amount of data, and they all use sub-databases and tables, so a unified unique ID is required for storage after sub-databases. This ID can be in increment
Distributed global unique ID generation strategy
Why a distributed system needs an ID generation system In a complex distributed system, it is often necessary to uniquely identify a large amount of data and messages. For example, in the financial
Rest – Can PROTOBUF FIELD MASK can be applied to GRPC unique?
Let’s take this example from the official doc:
// Updates a book.
rpc UpdateBook (UpdateBookRequest) returns (Book) {
// Update maps to HTTP PATCH. Resource name is mapped to a URL path.
//
PostgreSQL multi-column unique
I have a strange situation in PostgreSQL 9.4.
I have a table:
id integer NOT NULL DEFAULT nextval(‘users_userpropmeta_id_seq’::regclass)
name character varying(255) NOT NULL
cls character va
PostgreSQL – Postgres unique constraint is not forced uniqueness
This is my constraint:
CREATE UNIQUE INDEX index_subscriptions_on_user_id_and_class_type_id_and_deleted_at
ON subscriptions
USING btree
(user_id, class_type_id, deleted_at); This query pr
Ruby – Rails Model: Validates_Unique Ness_OF Will not delete the endless space before a unique check? Isn’t the front guide?
Suppose I implement validates_uniqueness_of on the username. If the name’maddy’ already exists, then it will accept the value’maddy’ as the unique value instead of’maddy’. It should remove both sid
Database – SQLite – Table Constraints Unique and Column Constraints Unique Differences between UniQue?
Questions about SQLite.
In CREATE TABLE SQL, we can add UNIQUE constraints in any way: column-constraint or table-constraint. My question is simple. Do they work differently?
The only d