auto-increment

问题 I am fairly new to SQL but have been working hard to learn. I am currently stuck on an issue with setting a primary key to have 8 digits no matter what. I tried using INT(8) but that didn't work. Also AUTO_INCREMENT doesn't work in PostgreSQL but I saw there were a couple of data types that auto increment but I still have the issue of the keys not being long enough. Basically I want to have numbers represent User IDs, starting at 10000000 and moving up. 00000001 and up would work too, it

问题 I want to know is there any SQL query for asp.net,c# that can just re arrange auto increment coloumn values.. eg. deleting 2 in the table: sno 1 2 3 4 does: sno 1 3 4 but i want re-arrangement: sno 1 2 3 Note: Don't want to to the numbering manually query to create table is like this: CREATE TABLE uid (sno int IDENTITY(1,1) PRIMARY KEY, qpname nvarchar(500), mob int, tm int) 回答1: Let your table be named Parent and table that will hold the backup is called Backup. They should have identical

问题 CREATE TABLE u_account ( Jid serial primary key, score int4 ); The primary key works fine (updates itself) ok when I update it like this; INSERT INTO u_account ('score') VALUES ('122233344'); However when I insert a value like this; INSERT INTO u_account VALUES ('122233344'); This updates the primary key; I don't want the primary key to accept anything other than the number that is supposed to be coming next. Someone had set it up for me before so that if I put in this code; INSERT INTO u

问题 I'm creating two tables: Code and Subcode. Each Code can have several subcodes. I would like to label Codes with numbers and subcodes with letters (e.g. 100A, 100B, 100C). How can this be accomplished in MySQL similar to using autoincrement? 回答1: Auto increment columns must be integer. One way to implement what you want is to use 16 bits of the column for the code, and the other 16 bits for the sub-code. MySQL will see a plain integer, and will be able to increment it. function decode($id) {

问题 Suppose we have a table with an auto-increment primary key. I want to load all IDs greater than the last ID I have seen. SELECT id FROM mytable WHERE id > 10; With the naive approach, I risk skipping IDs: Transaction 1 claims ID 11. Transaction 2 claims ID 12. Transaction 2 commits. I read all IDs >10. I see 12, and next time I will read all IDs >12. I have skipped 11. Transaction 1 commits. For all intents and purposes, ID 11 now exists. As a solution, I propose to do a double check to

问题 i would to execute this query but it doesn't work and i don't know why : $query = mysqli_query($connexionUser, "ALTER TABLE creatik AUTO_INCREMENT = '$i'"); i check my vars and there are okay. Auto increment is set on a id column who is primary key if it can help to understand what's wrong. Thanks to take a look :) 回答1: AUTO_INCREMENT expects an integer. It's possible that the quotes are throwing it off, try removing them. 来源： https://stackoverflow.com/questions/12588071/alter-table-table

问题 EMPLOYEE.java @Entity @Table(name="EMPLOYEE") public class Employee implements Serializable { @Id @GeneratedValue( strategy = GenerationType.TABLE) EMPLOYEE (TABLE) 1 3/13/2013 911 Jack Bauer 32768 3/13/2013 911 Jack Bauer 65536 3/13/2013 911 Jack Bauer 98304 3/13/2013 911 Jack Bauer HIBERNATE_SEQUENCES(TABLE) HOLDING CORRECT NUMBER EMPLOYEE 4 回答1: @TableGenerator(name="tabgen",table="employee-id",pkColumnName="name",valueColumnName="value",allocationSize=1) @GeneratedValue(strategy

问题 I have code which saves a String to a file. The problem is that the String is constantly changing (as they are sensor values) but the string is only saved once, then seems to delete the file once closed and open and new one to which it prints only one value. I need it to save each value to the same file, while auto-incrementing to avoid losing any data. Here is my code: UPDATED: I have updated this code to the working version. The code now saves the string to the file, then updates the file

问题 I have a table with an auto_increment column. I save the last value of the column in another table called ids_tbl, and when mysql restarts, read the value from ids_tbl and re-set the AUTO_INCREMENT value. If I do this: alter table outgoing_tbl auto_increment=500; it works But if I do this select @max_id:= max_id FROM ids_tbl; alter table outgoing_tbl auto_increment=@max_id; or if I do this: select @max_id:= max_id FROM ids_tbl; alter table outgoing_tbl auto_increment=(select @max_id); Then it

问题 I have two primary (composite) keys that refer to a shop and a branch. I thought I should have used a corresponding ID for each row, so I added a UNIQUE + AUTO_INCREMENT named ID. So I had on the table a column named ID (AUTO INCREMENT), but it was declared PRIMARY - which was done automatically, and I don't want the ID to be PRIMARY. Just the shop and branch. I have learnt how to trick MYSQL to accept the ID field as UNIQUE and AUTO INCREMENT, as it was not extremely trivial to make the AUTO