foreign-keys

I had this script which worked in sql server 2005 -- t-sql scriptlet to drop all constraints on a table DECLARE @database nvarchar(50) DECLARE @table nvarchar(50) set @database = 'dotnetnuke' set @table = 'tabs' DECLARE @sql nvarchar(255) WHILE EXISTS(select * from INFORMATION_SCHEMA.TABLE_CONSTRAINTS where constraint_catalog = @database and table_name = @table) BEGIN select @sql = 'ALTER TABLE ' + @table + ' DROP CONSTRAINT ' + CONSTRAINT_NAME from INFORMATION_SCHEMA.TABLE_CONSTRAINTS where constraint_catalog = @database and table_name = @table exec sp_executesql @sql END It does not work in

create table Machine ( Machine_ID int primary key, Machine_Name varchar(30) Machine_Title varchar(30) ) create table Part ( Part_ID int primary key, Part_Name varchar(30), Part_Description varchar(30) ) //How do I make this table below? create table Machine-Part ( Machine_ID int foreign key references (Machine.Machine_ID), Part_ID int foreign key references (Part.Part_ID) Factory_Note varchar(30); ) Mysql complains there is a problem with syntax? Desired Result: have Table 'Machine-Part' use 'Machine_ID' & 'Part_ID' as both primary keys (which are both foreign keys). If you declare the

This is my model. class User{ @CollectionOfElements @JoinTable(name = "user_type", joinColumns = @JoinColumn(name = "user_id")) @Column(name = "type", nullable = false) private List<String> types = new ArrayList<String>(); } You can imagin there would be a table called "user_type", which has two columns, one is "user_id", the other is "type". And when I use hbm2ddl to generate the ddls, I can have this table, along with the foreign key constraint on "user_id". However, there is no index of this for this column. And I need this index. How can I let hibernate to generate this index for me? Thank

Please have a look at the database design below: create table Person (id int identity, InvoiceID int not null) create table Invoice (id int identity, date datetime) Currently all persons have an invoiceID i.e. the InvoiceID is not null . I want to extend the database so that some person does not have an Invoice . The original developer hated nulls and never uses them. I want to be consistent so I am wondering if there are other patterns I can use to extend the database to meet this requirement. How can this be approached without using nulls? Please note that the two tables above are for

Trying to create a table with a foreign key. I keep getting ORA-00904 error. What am I doing wrong. Is it because table of the foreign key is not yet created ? CREATE TABLE ingredients( ingredient_id number(2,0), ingredient VARCHAR2(55) NOT NULL, quantity_required VARCHAR2(15) NOT NULL, optional_ingredient VARCHAR2(30) NOT NULL, CONSTRAINT pk_ingr_id PRIMARY KEY(ingredient_id), CONSTRAINT fk_ingredient_list FOREIGN KEY(id) REFERENCES ingredient_list(id) ); Take a look at the following line: CONSTRAINT fk_ingredient_list FOREIGN KEY(id) REFERENCES ingredient_list(id) Your table has no column