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Questions tagged [identifier]

An identifier is a name that identifies either a unique object or a unique class of objects.

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What is the meaning of single and double underscore before an object name?

What do single and double leading underscores before an object's name represent in Python?
Ram Rachum
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What's the Hi/Lo algorithm?

What's the Hi/Lo algorithm? I've found this in the NHibernate documentation (it's one method to generate unique keys, section 5.1.4.2), but I haven't found a good explanation of how it works. I know that Nhibernate handles it, and I don't need to…
DiegoCofre
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Is main a valid Java identifier?

One of my kids is taking Java in high school and had this on one of his tests: Which of the following is a valid identifier in Java? a. 123java b. main c. java1234 d. {abce e. )whoot He answered b and got it wrong. I looked at the question…
Gary Bak
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Hibernate throws org.hibernate.AnnotationException: No identifier specified for entity: com..domain.idea.MAE_MFEView

Why am I getting this exception? package com.domain.idea; import javax.persistence.CascadeType; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.JoinColumn; import javax.persistence.OneToOne; import…
Ramy
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Are PostgreSQL column names case-sensitive?

I have a db table say, persons in Postgres handed down by another team that has a column name say, "first_Name". Now am trying to use PG commander to query this table on this column-name. select * from persons where first_Name="xyz"; And it just…
5122014009
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What are "connecting characters" in Java identifiers?

I am reading for SCJP and I have a question regarding this line: Identifiers must start with a letter, a currency character ($), or a connecting character such as the underscore ( _ ). Identifiers cannot start with a number! It states that a…
LuckyLuke
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Cannot create a database table named 'user' in PostgreSQL

It seems PostgreSQL does not allow to create a database table named 'user'. But MySQL will allow to create such a table. Is that because it is a key word? But Hibernate cannot identify any issue (even if we set the PostgreSQLDialect).
Channa
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Using number as "index" (JSON)

Recently started digging in to JSON, and I'm currently trying to use a number as "identifier", which doesn't work out too well. foo:"bar" works fine, while 0:"bar" doesn't. var Game = { status: [ { 0:"val", …
Zar
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Table name as a PostgreSQL function parameter

I want to pass a table name as a parameter in a Postgres function. I tried this code: CREATE OR REPLACE FUNCTION some_f(param character varying) RETURNS integer AS $$ BEGIN IF EXISTS (select * from quote_ident($1) where…
John Doe
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Hibernate error: ids for this class must be manually assigned before calling save():

Caused by: org.springframework.orm.hibernate3.HibernateSystemException: ids for this class must be manually assigned before calling save(): com.rfid.model.Role; nested exception is org.hibernate.id.IdentifierGenerationException: ids for this class…
程序猿
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How to call on a function found on another file?

I'm recently starting to pick up C++ and the SFML library, and I was wondering if I defined a Sprite on a file appropriately called "player.cpp" how would I call it on my main loop located at "main.cpp"? Here is my code (Be aware that this is SFML…
user1932645
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9 answers

Are Python variables pointers? Or else, what are they?

Variables in Python are just pointers, as far as I know. Based on this rule, I can assume that the result for this code snippet: i = 5 j = i j = 3 print(i) would be 3. But I got an unexpected result for me, and it was 5. Moreover, my Python book…
Lior
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PostgreSQL Error: Relation already exists

I am trying to create a table that was dropped previously. But when I do the CREATE TABLE A ... I am getting below error: Relation 'A' already exists. I verified doing SELECT * FROM A, but then I got another error: Relation 'A' does not…
nsbm
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How does jQuery work when there are multiple elements with the same ID value?

I fetch data from Google's AdWords website which has multiple elements with the same id. Could you please explain why the following 3 queries doesn't result with the same answer (2)? Live Demo HTML:
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Misha Moroshko
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How to preserve identifierForVendor in ios after uninstalling ios app on device?

I am developing an iOS app which calls web-service for login and at that time i send login credentials to web server along with vendor identifier (identifierForVendor),to identify device uniquely for those credentials.So user can have only one…
Harshavardhan
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