identifier

问题 My app has just been rejected with the following message: PLA 3.3.12 We found that your app uses the iOS Advertising Identifier but does not include ad functionality. This does not comply with the terms of the iOS Developer Program License Agreement, as required by the App Store Review Guidelines. Specifically, section 3.3.12 of the iOS Developer Program License Agreement states: "You and Your Applications (and any third party with whom you have contracted to serve advertising) may use the

问题 This question already has answers here : How to determine if a string is a valid variable name? (5 answers) Closed 4 years ago . In Java, there are methods called isJavaIdentifierStart and isJavaIdentifierPart on the Character class that may be used to tell if a string is a valid Java identifier, like so: public boolean isJavaIdentifier(String s) { int n = s.length(); if (n==0) return false; if (!Character.isJavaIdentifierStart(s.charAt(0))) return false; for (int i = 1; i < n; i++) if (

问题 I'm trying to generate a unique ID in php in order to store user-uploaded content on a FS without conflicts. I'm using php, and at the moment this little snippet is responsible for generating the UID: $id = tempnam (".", ""); unlink($id); $id = substr($id, 2); This code is hideous: it creates a temporary file on the FS and deletes it, retaining only the relevant unique part of the generated string. Is there any better way to do this, most preferably without any external dependencies? Thanks

问题 Why does many sites (youtube is good example) generate string of random number and letter instead of using for example the row id? usually its something likes this bla?v=wli4l73Chc0 instead of like bla?id=83934 Is it just to keep it short if you have many rows? Or is there other good things about this? Because i can imagine: bla?id=23934234234 dont look so nice Thanks and cheers 回答1: They are actually not random strings. Normally they are numbers (usually row IDs) that are encoded in Base-36

问题 Is it possible with MySQL 5.5 to get the current transaction ID? Something like... BEGIN; SELECT CURRENT_XID(); -- foo ... SELECT CURRENT_XID(); -- also foo ROLLBACK; SELECT CURRENT_XID(); -- NOT foo The actual value isn't important, as long as I can get some unique identifier that will always return the same value throughout the same transaction. 回答1: Have a gander at http://dev.mysql.com/doc/refman/5.5/en/innodb-trx-table.html There is no simple function to return that information but you

问题 I have a simple question: In Java Compiler, Which type of method or variables can be defined as identifier (ID) or Keyword (reserved word)? For following example, ID should be : add , main , a , b , c , Test1 , What about print , is print an ID or keyword? Example: public class Test1 { public static int add(int a, int b) { return a + b; } public static void main() { int c; int a = 5; c = add(a, 10); if (c > 10) print("c = " + -c); else print(c); print("Hello World"); } } 回答1: An identifier is

问题 I'm doing some research to help me develop a REST API and this is one topic I haven't seen discussed in depth anywhere. If I have a user in the system, is it better to identify the user using a numeric identifier /users/1 Or using a string identifier? /users/RSmith I can see hypothetical potential pros and cons to each approach, string identifiers are more human readable, less discoverable (can't be incremented to find valid users), and don't require storing another numeric id in the database

问题 I'm doing some research to help me develop a REST API and this is one topic I haven't seen discussed in depth anywhere. If I have a user in the system, is it better to identify the user using a numeric identifier /users/1 Or using a string identifier? /users/RSmith I can see hypothetical potential pros and cons to each approach, string identifiers are more human readable, less discoverable (can't be incremented to find valid users), and don't require storing another numeric id in the database

问题 How can I get the label of each column in a result set to prepend the name if its table? I want this to happen for queries on single tables as well as joins. Example: SELECT first_name, last_name FROM person; I want the results to be: | person.first_name | person.last_name | |-------------------|------------------| | Wendy | Melvoin | | Lisa | Coleman | I could use "AS" to define an alias for each column, but that would be tedious. I want this to happen automatically. SELECT first_name AS

问题 How can I get the label of each column in a result set to prepend the name if its table? I want this to happen for queries on single tables as well as joins. Example: SELECT first_name, last_name FROM person; I want the results to be: | person.first_name | person.last_name | |-------------------|------------------| | Wendy | Melvoin | | Lisa | Coleman | I could use "AS" to define an alias for each column, but that would be tedious. I want this to happen automatically. SELECT first_name AS