I have a table named student with columns studentid, name, address, email, phone.
Each student may have multiple email-id and multiple phone numbers. I want to record all emails and phone numbers too. So, I manipulates the student table columns by removing email-id column and phone column And created another table studentemail with columns emailserialnumber , email-id. And one more table studentphone with columns phoneserialnumber , phone. student table consists of studentid, name, address columns. should I add anymore columns to student table to maintain relation with other tables. Now I have three tables. now how can I relate the tables using keys. I mean like which column should I make primary key and foreign key so that three tables are connected.
Thank you
Your studentemail and studentphone tables simply need another column to reference the student table. In your case, this would be the studentid column.
You can then bring the data together in a single query. I should note that you might want a column that specifies what the email and phone numbers are -- home, mobile, work, and so on.
Related
I had a very big excel spreadsheet that I moved into Access to try to deal with it easier. I'm very much a novice. I'm trying to use SQL via Access.
I need to assign a unique identifier to duplicates. I've seen people use DENSE_RANK in SQL but I can't get it to work in Access.
Here's what I'm trying to do: I have a large amount of patient and sample data (20k rows). My columns are called FULL_NAME, SAMPLE_NUM, and DATE_REC. Some patients have come in more than once and have multiple samples. I want to give each patient a unique ID that I want to call PATIENT_ID.
I can't figure out how to do this, aside from typing it out on each row. I would greatly appreciate help as I really don't know what I'm doing and there is no one at my work who can help.
To illustrate the previous answers' textual explanation, consider the following SQL action queries which can be run in an Access query window one by one or as VBA string queries with DAO's CurrentDb.Execute or DoCmd.RunSQL. The ALTER statements can be done in MSAcecss.exe.
Create a Patients table (make-table query)
SELECT DISTINCT s.FULL_NAME INTO myPatientsTable
FROM mySamplesTable s
WHERE s.FULL_NAME IS NOT NULL;
Add an autonumber field to new Patients table as a Primary Key
ALTER TABLE myPatientsTable ADD COLUMN PATIENT_ID AUTOINCREMENT NOT NULL PRIMARY KEY;
Add a blank Patient_ID column to Samples table
ALTER TABLE mySamplesTable ADD COLUMN PATIENT_ID INTEGER;
Update Patient_ID Column in Samples table using FULL_NAME field
UPDATE mySamplesTable s
INNER JOIN myPatientsTable p
ON s.[FULL_NAME] = p.[FULL_NAME]
SET s.PATIENT_ID = p.PATIENT_ID;
Maintain third-norm principles of relational databases and remove FULL_NAME field from Samples table
ALTER TABLE mySamplesTable DROP COLUMN FULL_NAME;
Then in a separate query, add a foreign key constraint on PATIENT_ID
ALTER TABLE mySamplesTable
ADD CONSTRAINT PatientRelationship
FOREIGN KEY (PATIENT_ID)
REFERENCES myPatientsTable (PATIENT_ID);
Sounds like FULL_NAME is currently the unique identifier. However, names make very poor unique identifiers and name parts should be in separate fields. Are you sure you don't have multiple patients with same name, e.g. John Smith?
You need a PatientInfo table and then the SampleData table. Do a query that pulls DISTINCT patient info (apparently this is only one field - FULL_NAME) and create a table that generates unique ID with autonumber field. Then build a query that joins tables on the two FULL_Name fields and updates a new field in SampleData called PatientID. Delete the FULL_Name field from SampleData.
The command to number rows in your table is [1]
ALTER TABLE MyTable ADD COLUMN ID AUTOINCREMENT;
Anyway as June7 pointed out it might not be a good idea to combine records just based on patient name as there might be duplicates. Better way will be treat each record as unique patient for now and have a way to fix patient ID when patient comes back. I would suggest to go this way:
create two new columns in your samples table
ID with autoincrement as per query above
patientID where you will copy values from ID column - for now they will be same. But in future they will diverge
copy columns patientID and patientName into separate table patients
now you can delete patientName column from samples table
add column imported to patients table to indicate, that there might be some other records that belong to this patient.
when patients come back you open his record, update all other info like address, phone, ... and look for all possible samples record that belong to him. If so, then fix patient id in those records.
Now you can switch imported indicator because this patient data are up to date.
After fixing patientID for samples records. You will end up with patients with no record in samples table. So you can go and delete them.
Unless you already have a natural key you will be corrupting this data when you run the distinct query and build a key from it. From your posting I would guess a natural key would be SAMPLE_NUM. Another problem is that if you roll up by last name you will almost certainly be combining different patients into one.
I'm working on a football statistics database, and in the table to store results of matches, I have two references to the primary key of a team table: one home, one away.
My intention is to create a query which returns the name of both of the teams, along with other details, but I can't think of a way to achieve this WITH the team names (my attempts so far can only produce one team name, with the other an ID number). I'll give the relation structure if this wasn't clear:
(PKs in bold, FKs asterisk)
team(team_id, team_name, venue)
match(match_id, home_team*, away_team*, home_score, away_score, date,)
My desired output would be a table with these columns:
home_team_name, home_team_score, away_team_score, away_team_name, date, venue
Is this possible with my tables, or should I change the way I store results?
When joining the team table to the match table in a query, you'll need to join the match table to the team table twice. You need to use an different alias for the teams each time.
I have a database having many tables and I want to make 2 columns from 2 different tables unique.
For example, 1 table named person contains fields like id, name,father_name,date of birth, res. address etc and other table named institute contains id (which is foreign key of id of person table), institute.
I have to make a combination of (name,father_name,date of birth, institute) unique. Can anybody help me??
I have a table students with the following fields.
Id,FirstName,SecondName,Photo,Student_ID
I also have a table called class_of_2011 with the fields
Id,FirstName,SecondName,Photo,Student_ID,Subjects
I want to select some specific students from table students and have them in table class_of_2011,but I already have the names in table students.I am thinking the only way to do this is to copy the names i want to the table class_of_2011,but since there will be a class of 2012 and beyond,I feel like I will be simply copying data from one table to the other.
Is repeating myself inevitable in my case?
It looks like this could be normalized easily. Why not have your class_of_ tables simply have a foreign key to the student table's id column?
StudentId,Subjects
In this way, one student record could be associated with several classes, in case someone is on the 5-year plan.
I'm assuming that the Student_ID field in the Students table is their id number or something, and not the primary key of that table.
Students Table
Id,FirstName,SecondName,Photo,Student_ID
Subjects Table
Id,Subject
Student_Subjects Table
Id,Student_Id,Subject_Id,Year
You may then assign a student multiple subjects, for multiple years.
The class_of_2011 table should contain the primary key of the students table and none of the other "repeated" data. All of the other columns you're interested in can then be obtained by joining the two columns together in a query.
I would restructure the data if possible... Something like....
Student Table
ID, Name, Address, other common specific to student
GraduatingClass Table
YearGraduate, StudentID
Enrollment Table
StudentID, ClassID, SemesterID
I am building my own CRM access database that will contain a list of contacts. I would like to have an opportunity reference one contact as an employee, and another as the customer. Is there a way that I can add employees using their internal user ID (always 4 digits) and autonumber customer contacts?
I don't plan on building forms until I am comfortable that everything is working properly in table view.
You cannot assign an ID to an autonumber field. I might suggest adding an employeeID field to your contacts table that would have the employee ID number. The contact ID would still be an autonumber, so in essence they would have two IDs, but their employeeID would need to be stored in a different field.
You can try something different, but you will likely run into a duplicate ID at some point. Use a seperate table for autonumber Customer IDs. When adding a customer into your contact table, you "insert" a new record into the separate customer ID table to get the autonumber ID. If you're inserting an employee, just use the EmployeeID as the contact ID. So you need to be very careful when mixing two ID systems. It's best to use 1 ID and then use the other ID in some other field.
Consider using two tables, one for contact fields and another for employee-specific fields. Put your AutoNumber field in the contact table, and put the employee id in the employee table. In the employee table, use a foreign key that refers to the AutoNumber field in the contact table.