auto-increment

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 6 years ago . I would like to insert values into mysql innodb table Auto_Increment column. I am loading some data from an old table to new table which has an identity, and need to preserve the existing values from the old

问题 I'm working on an object in C# where I need each instance of the object to have a unique id. My solution to this was simply to place a member variable I call idCount in the class and within the constructor I would have: objectID = idCount; idCount++; I thought that this would solve my problem but it seems that idCount never gets incremented even though the constructor gets called multiple times. For example if idCount = 1, the objectID for all the objects are still 1. Why doesn't idCount++

问题 I created a table using Android's Room library, which stores items of type User . For the ID column, the value is automatically generated by adding the annotation @PrimaryKey(autoGenerate = true) In the next application run, I delete all entries in the table. However, the auto-generated value is not reset to 0, but continues where it left of the previous run. How can I reset the auto-increment counter when I delete all entries in a table? 回答1: Why would you, is perhaps the more pertinent

问题 For the selected rows in a column, how to update each row sequentially from the beginning to the end, with each row value incremented by 1 (or certain number). I know this can be done in excel in few seconds but I could figure out how to achieve in SQL server. For instance: customer id is NULL now update customer id with every row incremented by 1 (i.e. first row = 1, second row = 2, .....nth row = n) ship-to party customer id 0002018092 NULL 0002008127 NULL 0002000129 NULL 0002031592 NULL

问题 i'm trying to set up a MySQL database for storing biological data. I have to extract this data from a file and i have a perl script for that. The problem i have is that i need three primary keys in order for them to be unique, and i want one of them to be an auto increment integer. I would like, however, the auto-incremented value to reset each time the combination of the first two keys changes. sequence1 | hit1 | 1 sequence1 | hit1 | 2 sequence1 | hit2 | 1 sequence2 | something | 1 sequence2

问题 I am using PHP and MySQL. Goal: Insert a new row into a table with an auto-increment id column. While inserting this new row, I would like to copy the new inserted row's auto-increment id # into another column in the same row/entry. Upon creation, the new entry/row should have the auto-incremented id column and another column with the same number. My biggest concern: I need all of this to happen correctly and reliably, even while other transactions from other connections could be taking place

问题 Using SQL Server 2008 R2 I'd like to have a table (already having a primary key on 2 columns) with a third column which is an autoincrement based on one of the two columns part of the primary key. In other terms, I would like when adding a new record to the table , have an autoincrement file AIfield automatically incremented as follows: PK1 PK2 AIfield ------------------ 1 A 1 1 B 2 1 C 3 2 A 1 2 B1 2 2 B2 3 2 C1 4 where PK1 and PK2 are the two fields of the primary key. I do not want to use

问题 I have to create a MySQL InnoDB table using a strictly sequential ID to each element in the table (row). There cannot be any gap in the IDs - each element has to have a different ID and they HAVE TO be sequentially assigned. Concurrent users create data on this table. I have experienced MySQL "auto-increment" behaviour where if a transaction fails, the PK number is not used, leaving a gap. I have read online complicated solutions that did not convince me and some other that dont really

问题 I'm new in Entity Framework and i have problem with something which was quite easy in pure t-sql. Assume that we have table with 3 columns. Id(identity, primary key), IdKind (int), Number(int). Column Nubmer depends on IdKind column. Data in this table should look like this: Id | IdKind | Number 1 | 1 | 1 2 | 1 | 2 3 | 1 | 3 4 | 2 | 1 5 | 2 | 2 6 | 2 | 3 As you can see column number is auto incremented depends on IdKind. In t-sql I was finding max(Number) + 1 for some IdKind. Everything was

问题 I am adding batches of records to a table using a single insert statement. I want each new batch to be allocated incrementing numbers, but starting from 1 each time. So, if I have Batch Name IncementingValue 1 Joe 1 1 Pete 2 1 Andy 3 2 Sue 1 2 Mike 2 2 Steve 3 and I then add two records (using a single insert statement) : 3 Dave 3 Paul How can I run an update statement against this table so that Dave will be set to 1 and Paul to 2. I don't want to use a cursor. 回答1: The ranking function ROW