What are the range of tactics available for selecting records on low selectivity columns? An example mig开发者_如何学JAVAht be an orders table where, over many years, you build up a large number of c
I am in the middle of optimizing the indexes in an SQL Server 2008 DB I\'m working on. Right now I\'m on the \"central\" table.
Recently NoSQL has gained immense popularity. What are the advantages 开发者_如何转开发of NoSQL over traditional RDBMS?Not all data is relational.For those situations, NoSQL can be helpful.
I\'m developing a document management system for my graduation project. In this project, users are adding documents\' metadata into my \"documents\" table in a relational database.
Given a schema R (A,B,C,D) with functional dependencies F = {A->B, A->C} I need to determine if R is in 3NF, but first I need to determine what the candidate keys are so I can determine if B and
Let me illustrate this question with a simplified example. Assume I am building a project using python with a PostgreSQL relational database. In my database I have two tables \"parent\" and \"child\"
please help me with my simple cakephp application. i have a products_warehouses table: -- -- Table structure for table `products_warehouses`
Good Overviews Generally speaking, you\'re making a decision between fast read times (for example, nested set) or fast write times (adjacency list). Usually, you end up with a combination of the optio
This question is about how to design a SQL relationship. I am pretty newbie in this matter and I\'d like to know the answers of (way) more experts guys...
I have a few models which are not in the default cakephp format user(id, name....) 1 Harsha ... 2 John ....
加载中,请稍侯......