relational-database

问题 how can i display a record in Cgridview? tbl_book: id title author tbl_in_out: id book_id date_out date_in I have created a relationship that the book_id in tbl_in_out belongs to id in tbl_book. what i want to do is to query a record in the tbl_in_out with the corresponding data in tbl_book and display it in the CGridview(sorry for the bad english). Please help! 回答1: Basic grid view: // the following code goes in your view $this->widget('zii.widgets.grid.CGridView', array( 'dataProvider'=>

问题 I have two database tables that contain information about land contracts. They are related with land_contract_annual_price.land_contract_id -> land_contract.land_contract_id . Table 'land_contract' Table 'land_contract_annual_price' If a land contract has the value "Rörligt pris" in the field land_contract_price_type, there are related values in the table land_contract_annual_price . At the moment I'm doing two queries, one to each table. I then merge the results and present the land contract

问题 Background: I have a database containing parents and children's names (this is a simplification of the actual data, but the analogy is close enough). Task: The database has to store an ordered list of children's names for each parent . Assumptions: The database will contain millions of parents, possibly more. Parents typically have no more than to 4 or 5 children, but rare (and even extreme) cases have to be supported as well. Children's names (as well as the ordering) tends to repeat a lot.

问题 Im trying to figure out what the appropriate way to setup a database would be given this scenario: I am creating a Movie / TV database. A movie may have multiple genres and a tv show may have multiple genres. Essentially what I am wondering is if you have a Movie table, TV table... should you: have a MovieHasGenre table consisting of a foreign key to the Movie table and a regular field for the genre value or have a MovieHasGenre table AND a Genre table where the MovieHasGenre has two foreign

问题 Ok so i have a table with the following columns col1 col2 col3 a a 1 a a 2 a b 3 a b 4 a b 5 so i have to split the above mentioned table into multiple tables while keeping col1 and col2 in a separate table and a primary key to foreign key relation with col3 in another table. This is how it looks. table1 Id col1 col2 table2 id col3 table1fk I was able to split the table into two tables but it created the duplicate rows in the table1 and mapped them to single row in table2. What i wanted to

问题 I am working on a health app and I'm designing a database (MySQL), which should store symptoms and diseases and bodyparts. The app will work as follows: User chooses gender, age and bodypart (front/back) App shows all (common/less common) symptoms of chosen bodypart User chooses symptom App shows all (common/less common) diseases of chosen symptom. User chooses disease App shows disease information I got some help so far, but I still need some help finding a solution: Making weight in symptom

问题 Given relation R(A,B,C,D,E) and FDs = {A->BC, CD->E, B->D, E->A} While converting R into BCNF: ABCDE -> BD & ABCE will be first decomposition BD is in BCNF Regarding ABCE: Opinion 1: ABCE has FDs: A->BCE, E->ABC, BC->AE Therefore its already in BCNF Opinion 2 ABCE has FDs: A->BC, E->ABC Therefore needs to be decomposed into ABC & AE I believe that first one should be correct because in second we are assuming that A->E and BC->E are not possible because D is not one of the attributes of the

问题 In a relational database (SQL), I have a parent entity that can have 0..n related child entities. The parent entity is uniquely identified in part by its collection of related child entities, such that I should not be able to have two similar parents with the same collection of children. So I could have Parent 1 with Child 1 and Child 2, and Parent 2 with Child 2 and Child 3, but I cannot have another parent with Child 2 and Child 3. Ideally, I would like to enforce this uniqueness using a

问题 I'm new to setting up relational databases. I'm trying to create two tables in MySQL, a USER table and a COMPANY table. Both should be able to have multiple phone numbers associated with them, so I created a PHONE table and wanted to have a one-to-many relationship from both COMPANY to PHONE, and from USER to PHONE. There only seem to two options in what I am trying to do: Keep two foreign keys in PHONE, one referencing COMPANY, and one referencing USER. They would both default to NULL and

问题 ppl, I've to develop a Database like this, Here, I've a list of words. I need to keep relevancy for each other word in a database. when a new word added, I need to be able to add a row as well as a column. One of my idea for this is like this, CREATE TABLE tbl_Words ( [WordID] BIGINT NOT NULL IDENTITY(1,1), // This s Primary Key [Word] VARCHAR(250) NOT NULL, // This s Unique.. ) CREATE TABLE tbl_WordRelevancy ( [RelID] BIGINT NOT NULL IDENTITY(1,1), // Primary Key [Word1] VARCHAR(250) NOT