constraints

I have an sqlite database structured as follows: CREATE TABLE IF NOT EXISTS Patient ( PatientId INTEGER PRIMARY KEY AUTOINCREMENT ); CREATE TABLE IF NOT EXISTS Event ( PatientId INTEGER REFERENCES Patient( PatientId ), DateTime TEXT, EventTypeCode TEXT, PRIMARY KEY( PatientId, DateTime, EventTypeCode ) ); CREATE TABLE IF NOT EXISTS Reading ( PatientId INTEGER REFERENCES Patient( PatientId ), DateTime TEXT REFERENCES Event (DateTime), EventTypeCode TEXT REFERENCES Event (EventTypeCode), Value REAL, PRIMARY KEY( PatientId, DateTime, EventTypeCode ) ); I insert a Patient with Id #1 then I run:

In my create script for my database create script looking something like this: CREATE TABLE IF NOT EXISTS `rabbits` ( `id` INT UNSIGNED NOT NULL AUTO_INCREMENT, `name` VARCHAR(255) NOT NULL, `main_page_id` INT UNSIGNED COMMENT 'What page is the main one', PRIMARY KEY (`id`), KEY `main_page_id` (`main_page_id`) ) ENGINE=InnoDB; CREATE TABLE IF NOT EXISTS `rabbit_pages` ( `id` INT UNSIGNED NOT NULL AUTO_INCREMENT, `rabbit_id` INT UNSIGNED NOT NULL, `title` VARCHAR(255) NOT NULL, `content` TEXT NOT NULL, PRIMARY KEY (`id`), KEY `rabbit_id` (`rabbit_id`), CONSTRAINT `fk_rabbits_pages` FOREIGN KEY

My table has two columns: startsAt endsAt Both hold date and time. I want to make following constraint: IF both columns are NOT NULL then range between startsAt and endsAt must not overlap with other ranges (from other rows). You can keep your separate timestamp columns and still use an exclusion constraint on an expression: CREATE TABLE tbl ( tbl_id serial PRIMARY KEY , starts_at timestamp , ends_at timestamp , EXCLUDE USING gist (tsrange(starts_at, ends_at) WITH &&) -- no overlapping ); Constructing a tsrange value without explicit bounds as tsrange(starts_at, ends_at) automatically assumes

I'm trying to solve a constraint processing problem in prolog. I need to pack 4 squares of 5x5,4x4,3x3 and 2x2 in a grid of 10x10. They may not overlap. My variables look like this: Name: SqX(i), i=1..10, domain: 1..10 Where X is either 5,4,3 or 2. The index i represents the row, the domain the column in the grid. My first constraints try to define the width and height of the squares. I formulate it as such: Constraint: SqX(i) > SqX(j)-X /\ i>j-X, range: i>0 /\ j>0 So that the possible points are constrained to be within X rows and columns from each other. Prolog however, stops on these

I am building a system that is a central repository for storing data from a number of other systems. A sync process is required to update the central repository when the other systems data is updated. There will be a sync_action table to identify which system the central repo needs to sync with and the type of sync required. There are set of defined actions that is very unlikely to change. A slimmed down system is below. As I see it I can approach this in two ways: Option 1 ) Have an Action table that has the 3 actions available. Have a sync_action table which uses a foreign key to reference