primary-key

Is it possible to make an auto-increment function in MySQL that combines alpha elements and numeric? I have an existing system with keys like QAb99, QAb101, QAd9003, etc. The max numeric portion ranges from 1 to 9999, while the letters begin with QA and range from QAa to QAd, etc. and will eventually pass QAd9999 to QAe1, etc. Is it better to manage generating new keys in SQL or outside of SQL (i.e. php script)? thanks. I asked this a while ago. Mysql doesn't do this unfortunately. I'd love it to, but it just doesn't. In php you could do it. Example: public function random_id_gen($length) { /

I am trying to copy a record in a table and change a few values with a stored procedure in SQL Server 2005. This is simple, but I also need to copy relationships in other tables with the new primary keys. As this proc is being used to batch copy records, I've found it difficult to store some relationship between old keys and new keys. Right now, I am grabbing new keys from the batch insert using OUTPUT INTO. ex: INSERT INTO table (column1, column2,...) OUTPUT INSERTED.PrimaryKey INTO @TableVariable SELECT column1, column2,... Is there a way like this to easily get the old keys inserted at the

This is my annotation I use to generate my Join Table. @OneToMany(cascade = CascadeType.ALL) @JoinTable(name = "service_operations", joinColumns = { @JoinColumn(name = "serviceId") }, inverseJoinColumns = { @JoinColumn(name = "operationId") }) public Set<Operation> getOperations() { return operations; } Considering this is a OneToMany association, my natural assumption is that this table would generate a [ Primary Key | Foreign Key ] table, however everytime I drop and re create the database it is not the case: mysql> describe workflow_services; +-------------+------------+------+-----+-------

A web application I am working on has encountered an unexpected 'bug' - The database of the app has two tables (among many others) called 'States' and 'Cities'. ' States ' table fields: ------------------------------------------- idStates | State | Lat | Long ------------------------------------------- ' idStates ' is an auto-incrementing primary key. ' Cities ' table fields: ---------------------------------------------------------- idAreaCode | idStates | City | Lat | Long ---------------------------------------------------------- ' idAreaCode ' is a primary key consisting of country code +

How can i give composite primary key in Rails without any gem? My first table in migration file: class CreateUsers < ActiveRecord::Migration def self.up create_table :users do |t| t.string :userid t.string :name t.string :address t.timestamps end end def self.down drop_table :users end end My second table in migration file: class CreateProjects < ActiveRecord::Migration def self.up create_table :projects do |t| t.string :title t.string :description t.timestamps end end def self.down drop_table :projects end end In my schema file: ActiveRecord::Schema.define(:version => 20110222044146) do

The following method I want to INSERT several records simultaneously. public void insert() { try { this.connection.setAutoCommit(false); PreparedStatement ps = this.connection.prepareStatement( "INSERT INTO COMPANY (NAME,Address) Values (?,?)", new String[]{"ID"}); ps.setString(1, "X01"); ps.setString(2, "Address1"); ps.addBatch(); ps.setString(1, "Y01"); ps.setString(2, "Address2"); ps.addBatch(); //EXCEPTION OCCURS HERE int[] numUpdates = ps.executeBatch(); for (int i = 0; i < numUpdates.length; i++) { System.out.println("Execution " + i + "successful: " + numUpdates[i] + " rows inserted");