auto-increment

I had to migrate from a mySql based ruby on rails app to using postgresql. No problems but one so far, and I don't know how to solve it. The migration of data brought ids along with it, and postgresql is now having problems with existing ids: it's not clear to me where it gets the value that it uses to determine the base for nextval: it certainly isn't the highest value in the column, although you might think that would be a good idea. In any case, it's now colliding with existing id values. id column, created from a standard RoR migration is defined as not null default nextval('geopoints_id

Basically I have a table that versions products, so it has two columns of interest, id | product_id id is an autoincrement column, product_id is just an int When a product is first created the product_id comes from the id , When the product is edited we duplicate the row, so the product_id is the same, but the id is different. so when we first create the product we do two queries, insert, then update table whatever set product_id = id where id = {the insert id} This works, but I am wondering if there is a way to do it in one query? Note we only have access to insert, update, delete. no

I am new user for MongoDB Database. In MongoDb whatever insert into some collection defaultly one field is added that is _id field. For Example: db.users.insert({"User_id":"1","User_Name":"xxx","Address":"yyyy"}) db.users.find() It shows { "_id" : ObjectId("528475fc326b403f580d2eba"), "User_id" : "1", "User_Name" : "xxx",Address" : "yyyy" } I don't need _id field and i want to replace that _id field to User_id with auto increment values. Is it possible. Please help me. Thanks in advance. _id field is really special in mongodb. This is your primary key there and there is no way you can have a

I'm having a strange issue with some auto-inc IDs on a table, where instead of going up by 1 each time, it seems to be going up by 10 each time. I'm using the ClearDB MySQL Addon for Heroku PHP 5.5.15 Apache 2.4.10 Laravel dev branch (4.something) I've created the database via artisan's migrate functionality, My migration for the database table is <?php use Illuminate\Database\Schema\Blueprint; use Illuminate\Database\Migrations\Migration; class CreateCheckinTable extends Migration { /** * Run the migrations. * * @return void */ public function up() { Schema::create('checkins', function

In my db application I have a requirement for a unique, 4-digit number field for each customer. Up until 9999 I can just use autoincrements, but after that I will have to reuse numbers of customers that have been deleted (there won't be more than 5000 customers at a given time but there may be more than 9999 customers over the lifetime of the system). Question 1: Is there a (My)SQL statement to find the next reusable free number? Question 2: If I get the number, assign it to a new customer and save the customer all in one transaction, similar transactions taking place at the same time will be

I'm using C# 2010 Express. I have created a SQL Server CE database file ( .sdf ) then created Information table and ID, Name, City columns with Database Explorer. I want to save names and city user will write to the form. The auto-increment option is disabled in Database explorer and Properties windows. When I'm saving something to that database i must change the ID manually, how can I make ID column auto-increment enabled? There is a simple way for SQL CE: ALTER TABLE TableName ALTER COLUMN ColumnName IDENTITY (/*seed*/1, /*increment*/1) 来源： https://stackoverflow.com/questions/5052922/how-to