auto-increment | 易学教程

Android Room - Reset auto generated key on each app run

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问题 I'm using Room in order to persist data. I have a Entity that has a automatically generated (autoGenerate) primary key that mimics a ticket system. Entity: @Entity public class SequenceAction { @PrimaryKey(autoGenerate = true) private Integer sequenceId; private String actionType; private String extraInfo; //getters&setters } Initialization: sequenceAction = new SequenceAction(); sequenceAction.setActionType(COLLECT_ALL); sequenceAction.setExtraInfo("id = " + ids.get(i)); //run this line with

mysqldump - Export structure only without autoincrement

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问题 I have a MySQL database and I am trying to find a way to export its structure only, without the auto increment values. mysqldump --no-data would almost do the job, but it keeps the auto_increment values. Is there any way to do it without using PHPMyAdmin (that I know it can do it)? 回答1: You can do this : mysqldump -u root -p -h <db-host> --opt <db-name> -d --single-transaction | sed 's/ AUTO_INCREMENT=[0-9]*\b//' > <filename>.sql As mentioned by others, If you want sed to works properly, add

Create autoincrement key in Java DB using NetBeans IDE

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I'm coming from MySQL world, please help. Is it possible to create autoincrement key from NetBeans IDE in JavaDB? Do you use some more advanced db clients, which? Thanks. user28864 Found a way of setting auto increment in netbeans 8.0.1 here on StackoOverflow Screenshot below: Sam This may help you: CREATE TABLE "custinf" ( "CUST_ID" INT not null primary key GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1), "FNAME" VARCHAR(50), "LNAME" VARCHAR(50), "ADDR" VARCHAR(100), "SUBURB" VARCHAR(20), "PCODE" INTEGER, "PHONE" INTEGER, "MOB" INTEGER, "EMAIL" VARCHAR(100), "COMM" VARCHAR(450) );

AUTOINCREMENT is only allowed on an INTEGER PRIMARY KEY - android

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问题 I'm trying to create a table in my DB with an ID that is autoincrement itself but whenever I try to add the AUTOINCREMENT keyword to my query it tells me that : AUTOINCREMENT is only allowed on an INTEGER PRIMARY KEY Here is my query: @Override public void onCreate(SQLiteDatabase db) { String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_TASKS + " ( " + KEY_ID + "INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_NOTETITLE + " TEXT, " + KEY_NOTECONTENT + " Text, " + KEY_STATUS + " INTEGER)"; db.execSQL

How to turn off auto_increment in Rails Active Record

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问题 Is it possible to create primary key without auto_increment flag in ActiveRecord ? I can't do create table :blah, :id => false because I want to have primary key index on the column. I looked up documentation but didn't find anything useful. Is it possible to create primary key without auto_increment? 回答1: Try this? create_table(:table_name, :id => false) do |t| t.integer :id, :options => 'PRIMARY KEY' end 回答2: Okay, the question is old and the OP did not specify versions. None of the answers

sqlite: multi-column primary key with an auto increment column

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问题 I basically want to convert a table from mysql to sqlite with the following scheme: create table items ( id integer auto_increment, version integer default 0, primary key (id, version) ); Essentially, I want ID to auto increment whenever I insert anything into the table, with VERSION starting off at 0, but still allow multiple items with the same ID as long as VERSION is different. I'm trying to replicate this behavior with Sqlite however, I can't seem to get table creation working. It seems

How do I add a auto_increment primary key in SQL Server database?

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I have a table set up that currently has no primary key. All I need to do is add a primary key, no null, auto_increment . I'm working with a Microsoft SQL Server database. I understand that it can't be done in a single command but every command I try keeps returning syntax errors. edit --------------- I have created the primary key and even set it as not null. However, I can't set up the auto_increment . I've tried: ALTER TABLE tableName MODIFY id NVARCHAR(20) auto_increment ALTER TABLE tableName ALTER COLUMN id NVARCHAR(20) auto_increment ALTER TABLE tableName MODIFY id NVARCHAR(20) auto

Change the step auto_increment fields increment by

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问题 How do I change the amount auto_increment fields in MySQL increment by from the default (1) to n? 回答1: If you want to change autoincrement step from 1 to N then there is a solution. It could be done on MySQL server side: look for '--auto-increment-increment' startup option or use following command SET @@auto_increment_increment=2; , but be warned that this is a server wide change (all tables will increment by 2). Unortodox solutions could that could be considered: Launch two MySQL servers on

How to add an auto-incrementing primary key to an existing table, in PostgreSQL?

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I have a table with existing data. Is there a way to add a primary key without deleting and re-creating the table? leonbloy ( Updated - Thanks to the people who commented ) Modern Versions of PostgreSQL Suppose you have a table named test1 , to which you want to add an auto-incrementing, primary-key id (surrogate) column. The following command should be sufficient in recent versions of PostgreSQL: ALTER TABLE test1 ADD COLUMN id SERIAL PRIMARY KEY; Older Versions of PostgreSQL In old versions of PostgreSQL (prior to 8.x?) you had to do all the dirty work. The following sequence of commands

What are the overheads of using AUTOINCREMENT for SQLite on Android?

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In the SQLite Documentation, it includes the following :- The AUTOINCREMENT keyword imposes extra CPU, memory, disk space, and disk I/O overhead and should be avoided if not strictly needed. It is usually not needed. and The behavior implemented by the AUTOINCREMENT keyword is subtly different from the default behavior. With AUTOINCREMENT, rows with automatically selected ROWIDs are guaranteed to have ROWIDs that have never been used before by the same table in the same database. And the automatically generated ROWIDs are guaranteed to be monotonically increasing. These are important