I am creating a relational database for a friend and I have never used MS Access before. I am trying to make it so that the related values are shown on a table view rather than the numeric representation. For example, instead of
[1][2242], [2][443]
I would like
[1][John Smith], [2][Marilyn Monroe]
(the first value being the primary key and the second being the value linked to another table).
I have read this page about creating relationships between tables but I am still having trouble "viewing" the linked values. Microsoft Access is going to be the only way my friend is going to be viewing these results so that is why it is important to be able to see the correct values.
I have made relational databases before but only with traditional PHP and SQL and so I know what I need to do but I cannot seem to do it.
Any help would be appreciated.
Do not be misled into creating lookup values in tables. Create a form and add comboboxes to display the data from the related table, or use queries.
For example: create form to add records in multiple tables
Or
SELECT Id, Fullname FROM Table1
INNER JOIN Table2
ON Table1.FKID = Table2.ID
You can create the relationships visually in MS Access. You can also build queries in the query design window.
Related
Alright, I realize that what I am about to ask may not be possible, which I can live with. But If it is possible it will make my life a lot easier.
Within my MS Access Database, I am attempting to query 2 tables. These tables are both linked to my Access DB, one is linked to an Excel file (MSSB Reps DTP) containing a dump from a seperate DB2 database.
The other table in my query (SalesPage DNK Rep Query) is linked to another Access DB, which is in turn linked to a SQL databse. Here is an image of the Query design screen:
Where the tables are linked is not so much important as the fact that since they are linked tables, and since this is MS Access, I can not edit the tables. Therefore, I can not simply pop into design mode of either table and change the data type of a given column.
Each table has a column named CRD Number. I want to create an inner join between these two tables based on this column. Just a simple, everyday, inner join. I can not however, because the CRD Number column is stored as a Number for the MSSB Reps DTP table, and as text in the SalesPage DNK Rep Query table.
I was wondering if there is some way to temporarily use a fucntion to "cast" the CRD Number column fromo the MSSB Reps DTP table as text, so that I can run this query. However, any solution will be appreciated. Just don't tell me to edit the Excel document. I am trying very hard to avoid that for various reasons.
You can use CStr to cast the number as text.
SELECT *
FROM
[MSSB Reps DTP] AS m
INNER JOIN [SalesPage DNK Rep Query] AS s
ON CStr(m.[CRD Number]) = s.[CRD Number];
The Access query designer may refuse to display that join in Design View, but you can switch to SQL View and edit the statement text.
The table names are variable, but what is certain is that SELECT only is allowed and certain tables are excluded (ie Users, Log). I'm making a reporting form where a user can just enter sql queries to make template reports.
SELECT 'field1' As 'foo', 'field2' as 'bar'.. 'fieldn'
FROM 'table1',..'tablen'
JOIN ... ON ...
WHERE CONDITION
Although I'm thinking I can have the table names in a html select list of existing tables.
Also make a user reporter_appname#localhost with SELECT access only to all tables except Users and Log? In that case I won't need to bother with a regex check of the query?
(This would be in PHP)
(Ideally I just wanted a single textarea where the admin can just type their query, my report function would then take the output and present it nicely etc.)
I suggest you re-think your design.
Identifying valid select statements (and excluding all other statements) is basically impossible without completely parsing SQL. A regex is not going to be up to the task.
Even if you allow only select statements, users could perform denial-of-service attacks on your database. It is very easy to create select statements that run forever (we've all done it). A malicious user could crash your site in a hurry. And even well-intentioned users might do this by accident.
It would be much better to give the users more limited options for creating reports. Let them select certain tables and columns from a list, and create the appropriate query for them.
There is probably free MySQL reporting software out there that could serve as a good starting point, though I don't have any experience with this myself.
I think that you should rethink the design of your application.
The Users and Log tables should be on one database and the tables with the data for the reports should be on another database.
If you have them all in one database already just create another database, link them and then create synonyms from one database to another only for the tables that the user can access via his queries.
The user will run his queries on the database you have just created and he will be limited to those tables that have synonyms on it.
I do not know if this would be the best option because your description of the case is relatively vague but based on the information I have this could be a solution.
Within my database i have 3 different tables for different members. When saving the members details i use a form to save the members all to the same table but i would like to save them to a specific table depending on their details. for example if a member has registered with their school email i would like them to be saved within the student table, if they have used a freemail email address to be saved in the freemail table etc
Would this be run as a query or sorting the one table using if statements?
You probably should not have three tables, just a field that defines the member type. You may wish to read Fundamentals of Relational Database Design.
If you really insist on having three tables, even though it is likely to cause ever more tangled scenarios, you will either have to use VBA to gather the data from an unbound form and then fill it into the appropriate table, or ask the user which table they wish to update before you start and set up the form for that table.
It depends on your development environment. You can either change the switch to an If clause at business level or you can implement it as a database procedure. It's up to you.
http://msdn.microsoft.com/en-us/library/aa933214(v=sql.80).aspx explains how to use If clause in database
I am a bit rusty with mysql and trying to jump in again..So sorry if this is too easy of a question.
I basically created a data model that has a table called "Master" with required fields of a name and an IDcode and a then a "Details" table with a foreign key of IDcode.
Now here's where its getting tricky..I am entering:
INSERT INTO Details (Name, UpdateDate) Values (name, updateDate)
I get an error: saying IDcode on details doesn't have a default value..so I add one then it complains that Field 'Master_IDcode' doesn't have a default value
It all makes sense but I'm wondering if there's any easy way to do what I am trying to do. I want to add data into details and if no IDcode exists, I want to add an entry into the master table. The problem is I have to first add the name to the fund Master..wait for a unique ID to be generated(for IDcode) then figure that out and add it to my query when I enter the master data. As you can imagine the queries are going to probably get quite long since I have many tables.
Is there an easier way? where everytime I add something it searches by name if a foreign key exists and if not it adds it on all the tables that its linked to? Is there a standard way people do this? I can't imagine with all the complex databases out there people have not figured out a more easier way.
Sorry if this question doesn't make sense. I can add more information if needed.
p.s. this maybe a different question but I have heard of Django for python and that it helps creates queries..would it help my situation?
Thanks so much in advance :-)
(decided to expand on the comments above and put it into an answer)
I suggest creating a set of staging tables in your database (one for each data set/file).
Then use LOAD DATA INFILE (or insert the rows in batches) into those staging tables.
Make sure you drop indexes before the load, and re-create what you need after the data is loaded.
You can then make a single pass over the staging table to create the missing master records. For example, let's say that one of your staging table contains a country code that should be used as a masterID. You could add the master record by doing something along the lines of:
insert
into master_table(country_code)
select distinct s.country_code
from staging_table s
left join master_table m on(s.country_code = m.country_code)
where m.country_code is null;
Then you can proceed and insert the rows into the "real" tables, knowing that all detail rows references a valid master record.
If you need to get reference information along with the data (such as translating some code) you can do this with a simple join. Also, if you want to filter rows by some other table this is now also very easy.
insert
into real_table_x(
key
,colA
,colB
,colC
,computed_column_not_present_in_staging_table
,understandableCode
)
select x.key
,x.colA
,x.colB
,x.colC
,(x.colA + x.colB) / x.colC
,c.understandableCode
from staging_table_x x
join code_translation c on(x.strange_code = c.strange_code);
This approach is a very efficient one and it scales very nicely. Variations of the above are commonly used in the ETL part of data warehouses to load massive amounts of data.
One caveat with MySQL is that it doesn't support hash joins, which is a join mechanism very suitable to fully join two tables. MySQL uses nested loops instead, which mean that you need to index the join columns very carefully.
InnoDB tables with their clustering feature on the primary key can help to make this a bit more efficient.
One last point. When you have the staging data inside the database, it is easy to add some analysis of the data and put aside "bad" rows in a separate table. You can then inspect the data using SQL instead of wading through csv files in yuor editor.
I don't think there's one-step way to do this.
What I do is issue a
INSERT IGNORE (..) values (..)
to the master table, wich will either create the row if it doesn't exist, or do nothing, and then issue a
SELECT id FROM master where someUniqueAttribute = ..
The other option would be stored procedures/triggers, but they are still pretty new in MySQL and I doubt wether this would help performance.
I have this assignment that I think someone should be able to help me. I have 5 ACCESS databases wvrapnaoh.accdb, wvrappaul.accdb, ....etc. These databases have about 45 tables each and 15 forms. The good part is the structure, the name and the fields of each table in all the databases are all the same except the data or the records are different. For example I have a stress table in wvrapnoah as well as wvrappaul with the same fields in both tables but different data or records.
So, I need to merge all these five into a new Access database that will have the same structure as the 5 databases but will include the complete data that is all the records from the 5 databases merged into this new database.The same applies to even the 15 forms. It does not seem to be having a primary key I guess. I was planning to add a field for each table that would give me the name of the database as well from which it was merged. Example I will add a DBName field in Wvrapnoah in all the tables and add the name Noah in that field for all the records in each table. I basically need to automate this code.
I need a script (VBA or anything) so that the guys creating these databases can just run this script the next time and merge the databases.
Talking about the 'table' part of the problem:
Questions
Are the databases / table names defined or you don't know them?
Are you able to use linked tables?
I believe the straightforward way to merge all of them is to link all tables into a single access DB and then run a UNION ALL query. It would be something like this:
SELECT "HANK", *
FROM MyTableHank
UNION ALL
SELECT "JOHN", *
FROM MyTableJohn;
Notice I defined a field to identify the origin of the data being merged ("HANK", "JOHN"), as you suggested above.
About the forms, I believe you'll need to import them and then review the whole code. It basically depends on what the forms are doing. If they're query-based won't be a big deal (importing / fixing the queries, will make the form works). However, if the forms are related to the tables, you'll have more work to do.