relational-database

Ticket Vname Nname 1 Oli Seitz 1 Andi Hofmann 2 Oli Seitz 2 Oli Schmidt 2 Tim Schmidt 3 Tim Hofmann This table represents a mapping of persons ( Vname, Nname ) and tickets ( Ticket ). Vname and Nname together identify a person, but every Person ( Vname, Nname ) can have multiple tickets ( Ticket ), and a ticket can be assigned to multiple people. The PK in this table are all three columns together. So this table should be 1NF because there is no multi dimensional data in one column. But then I struggle. I think it is 2NF and 3NF because I can´t find any functional dependencies. (Hope they are

Assume a simple database for hotel reservations with three tables. Table 1: Reservations This table contains a check-in and check-out date as well as a reference to one or more rooms and a coupon if applicable. Table 2: Rooms This table holds the data of all the hotel rooms with prices per night and number of beds. Table 3: Coupons This table holds the data of all the coupons. Option #1: If you want to get an overview of the reservations for a particular month with the total cost of each reservation, you'd have to fetch the reservations, the rooms for each reservation, and the coupon (if one

This question already has an answer here: Sqlite delete query error 3 answers I am trying to alias a table in SQLite, for example by the following command: (it is from the book i am reading"Database Management Systems by Ramakrishnan") DELETE FROM Students S WHERE S.sid=12546 This code gives a syntax error. Without aliasing, the following code works: DELETE FROM Students WHERE sid=12546 But, if i want to alias the table, what should i do? Can anyone help? Thanks The DELETE statement operates on a single table and does not use a table alias. so you will have to use your query as : DELETE FROM

Is there a way to distribute a (smallish) self-contained relational database along with an Windows application that does not require users to install additional dependencies such as MS Access, SQL Server, MySQL, SQLite, etc.? Only the application will be accessing the database - not users directly. Microsoft SQL Server Compact 4.0 SQL Server Compact Edition 3.5 SQLite to name just a few. SQL Server Compact Edition 4 I would embed SQLite in my application. There's various ways to do this depending on the language your are using. 来源： https://stackoverflow.com/questions/4789908/self-contained

Postgres version : 9.1.x. Say I have the following Schema: DROP TABLE IF EXISTS posts CASCADE; DROP TYPE IF EXISTS quotes CASCADE; CREATE TYPE quotes AS ( text CHARACTER VARYING, is_direct CHARACTER VARYING ); CREATE TABLE posts ( body CHARACTER VARYING, q quotes[] ); And I wish to perform the following insert, shown in SQL, but from Python Psycopg2. insert into posts(body,q) VALUES('ninjas rock',ARRAY[ ROW('I AGREE',True)::quotes, ROW('I DISAGREE',FALSE)::quotes ]); What is the syntax to achieve this (without loops and such). I am sure it is possible since the documentation says "Changed in

I have a small question concerning with how I should design my database. I have a table dogs for an animal shelter and I have a table owners. In the table dogs all dogs that are and once were in the shelter are being put. Now I want to make a relation between the table dogs and the table owners. The problem is, in this example not all dogs have an owner, and since an owner can have more than one dog, a possible foreign key should be put in the table dogs (a dog can't have more than one owner, at least not in the administration of the shelter). But if I do that, some dogs (the ones in the

I have to save this information in a database Person -> is married to -> Person Where should I save that information? What is the proper design pattern should I apply here? Thank you! If you can only be maried to one person: 1:1 ------------- - Person - ------------- id (key) maried_to_id (foreign key) If you can be maried to more than one person or want to keep track of previous mariages, n:n ------------- - Person - ------------- person_id (key) ------------- - Mariage - ------------- first_person_id (foreign key) second_person_id (foreign key) start_date end_date (also first_person_id +