OK, I think you need to break this out into the basic “varieties”. You have two “entity”-style objects: User Campaign You have one “mapping”-style object: UserCampaign You have one “transactional”-style object: Click Step 1: entity Let’s start with the easy ones: User & Campaign. These are truly two separate objects, neither one really depends on … Read more
Certain issues need to be clarified and resolved before we can enter into a reasonable discussion. Pre-requisite Resolution Labels In a profession that demands precision, it is important that we use precise labels, to avoid confusion, and so that we can communicate without having to use long-winded descriptions and qualifiers. What you have posted as … Read more
Joins are used to combine two related tables together. In your example, you can combine the Employee table and the Department table, like so: SELECT FNAME, LNAME, DNAME FROM EMPLOYEE INNER JOIN DEPARTMENT ON EMPLOYEE.DNO=DEPARTMENT.DNUMBER This would result in a recordset like: FNAME LNAME DNAME —– —– —– John Smith Research John Doe Administration I … Read more
The manual: SELECT current_user; — user name of current execution context SELECT session_user; — session user name Meaning, session_user shows the role you connected with, and current_user shows the role you are currently operating with, for instance after calling SET role some_other_role;.
Yes. Ensures that you don’t have an orphan (entry with no parent), and depending on usage, if you define a cascading delete, when a parent is deleted, all its children will also be deleted. Disadvantage would be a slight performance hit just like any other foreign key.
You have this python code: c.execute(“insert into medicoes values(?,?,?,?,?,?,?)” % keys) which I think should be c.execute(“insert into medicoes values (?,?,?,?,?,?,?)”, keys) since the % operator expects the string to its left to contain formatting codes. Now all you need to make this work is for keys to be a tuple (or list) containing the … Read more
Another solution is to precreate 100 rows and instead of INSERT use UPDATE to update the oldest row. Assuming that the table has a datetime field, the query UPDATE … WHERE datetime = (SELECT min(datetime) FROM logtable) can do the job. Edit: display the last 100 entries SELECT * FROM logtable ORDER BY datetime DESC … Read more
I’m no couchdb expert, but after having done a little research this is what I’ve found. The simple answer is, use UUIDs unless you have a good reason not to. The longer answer is, it depends on: Cost of changing ID Vs How likely the ID is to change Low cost of changing and likely … Read more
It is excellent for staging mock tables when testing. For example, if your source tables contain millions of records and you want to test a small subset of data, you can use synonyms to re-direct the source table to a smaller table you control so you can stage various scenarios. In this way, you can … Read more
A year is an integer and even supports integer arithmetic in a meaningful way so text makes no sense. You don’t have a month or day so date is right out the window. The fine manual has this to say about smallint: The smallint type is generally only used if disk space is at a … Read more