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Hi all,
I have a table called Singer and another called Song in Access. The Singer table has a primary key of SingerID and the Song table has a primary key of SongID and a foreign key of SingerID. I'm trying to add data to the Song table and I'm getting the error, "You cannot add or change a record because a related record is required in table 'Singer'. Why am I getting that error? Any help will be greatly appreciated, thanks in advance for your help.
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A Singer must exist before a Song can be sung by the singer.
Bastard Programmer from Hell 
if you can't read my code, try converting it here[^]
modified 25-Aug-12 12:48pm.
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Hi Eddy, thanks for replying.
So you are saying that I will get the error message I mentioned if I try to add a song into the Song table before I add an singer for that song in the Singer table?
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Yes. The song you try to enter does not have a (valid) SingerId. Create a singer, like "Fat Lady", give her number 1 and enter your song with her SingerId. You'll find that the song will be accepted.
If you want to "point" to other tables from your Song-table, then the data in the other table has to exist before the Foreign Key is entered.
Bastard Programmer from Hell
if you can't read my code, try converting it here[^]
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C:\Projects\KCDXlogger>dbt kcdx "describe Artist ; describe Title ; describe Playlist
DBT V6.0 -- Simple SQL interface Sir John E. Boucher 2003
describe Artist
Name Type1 Type2 Nullable Unique Read only
---- ------------- -------------------- -------- ------ ---------
Id System.Guid DBTYPE_GUID True False False
Name System.String DBTYPE_WVARCHAR(255) True False False
2 records affected.
describe Title
Name Type1 Type2 Nullable Unique Read only
---- ------------- -------------------- -------- ------ ---------
Id System.Guid DBTYPE_GUID True False False
Name System.String DBTYPE_WVARCHAR(255) True False False
2 records affected.
describe Playlist
Name Type1 Type2 Nullable Unique Read only
-------- --------------- -------------------- -------- ------ ---------
CreTim System.DateTime DBTYPE_DATE True False False
Text System.String DBTYPE_WVARCHAR(255) True False False
PlaTim System.DateTime DBTYPE_DATE True False False
ArtistId System.Guid DBTYPE_GUID True False False
TitleId System.Guid DBTYPE_GUID True False False
5 records affected.
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Thank you all for replying. I have solved this problem. It is as someone had said, you can't create a song before you have a singer.
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Yes, which is very limiting, no?
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PIEBALDconsult wrote: Yes, which is very limiting, no?
Yes, it is. But that was not his original question, it was about referential integrity. So his statement can be rewritten as
you can't create a song before you have singers.
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Shameel wrote: you can't create a song before you have singers.
Don't be shocked too much, but I lied (just a little bit). Of course it's possible with the correct schema;
| Id | SongWriter |
|---|
| 1 | Paul McCartney | | 2 | Mick Jones |
| Song | WrittenBy |
|---|
| 1 | A world without love |
You can't have a singer sing a song before the song is written.
Creating a table-structure can be hard; a schema that has already been tried and used by a coworker, is a schema that has probably been tested by the co-workers user-base. Meaning, there's little chance that his code contains errors.
..and sometimes, you have to answer beyond the scope of the question. That must be what I enjoy most of the forums; reading strange questions and strange answers that make you go "hmz". Sometimes one can add a helpful answer, sometimes it's merely a waste of time. The most interesting discussions often start with "care to explain" or "why do you.."
Do keep up the good work and keep answering questions; not only will it have saved a few people quite some time and frustration, it's also a very efficient way of learning.
Bastard Programmer from Hell
if you can't read my code, try converting it here[^]
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ok, I get you. I made a pretty bad assumptions that the singer is the writer. 
Eddy Vluggen wrote: Do keep up the good work and keep answering questions; not only will it have saved a few people quite some time and frustration, it's also a very efficient way of learning.
I agree. I started learning many things when I started answering questions here. Helping others is a great way of learning.
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Shameel wrote: the singer is the writer
I don't think the OP is concerned with the writer at all.
And if he wanted to track writers he would still be best served by a many-to-many schema.
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Right, but the cause of the problem is a limiting schema. He wanted to create a song before he had singers, therefore the schema was the problem, not the code. 
A better schema allows one to add either first and then associate them later. And furthermore, his way requires you to add duplicates of a song that is performed by many singers -- which is bad.
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Hi
string conn = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
MySqlConnection con = new MySqlConnection(conn);
MySqlCommand cmd = new MySqlCommand();
cmd.Connection = con;
cmd.CommandText = "Insert_Image";
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("?description", SqlDbType.VarChar).Value = txtdesc.Text;
cmd.Parameters.AddWithValue("?fullstr", SqlDbType.VarChar).Value = path;
con.Open();
cmd.ExecuteNonQuery();
cmd.Connection.Close();
Session.RemoveAll();
My code is giving error at executenonquery, "Input string not in correct format". The values in path and txt dec are correct.
Can you please tell where i am wrong?
Regards
Inderjeet Kaur
Inderjeet Kaur
Sr. Software Engg
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The AddWithValue method expects the actual value to be passed rather than the data types, so you should write something like:
cmd.Parameters.AddWithValue("?description", txtdesc.Text);
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Thanks alot!
I am new to MY SQL database and my problem is solved.
Inderjeet Kaur
Sr. Software Engg
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You're welcome.
However, this problem isn't related to My SQL in any way, rather it is to do with ADO.NET.
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When I use MySQL I use an at (@), not a question mark (?) -- I thought that was the problem, does it work with the question mark?
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Dunno, but it works without any mark too. I only use the @-sign within the Sql-statement, the AddWithValue method always without.
Bastard Programmer from Hell
if you can't read my code, try converting it here[^]
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i am new to databse design. i want to design a schema for my bug tracking project . dont know how to start !!
plz help
Himanshu.
himanshu_1002@yahoo.com
Himanshu
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This[^] may help you to start.
Niladri Biswas
(Code Project MVP 2012)
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thanks Niladri.. this was helpful
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Learn to Normalize. A simple set of rules that can be applied to any collection of facts, and which results in a relational and normalized dataset.
Bastard Programmer from Hell
if you can't read my code, try converting it here[^]
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Dear all,
I'm new comer in SQL, I have problem in web development, in my system there is searching for phonetic name like nielsen and nelson. Example:
If I enter test word 'nielsen' then output can be 'nilsen','nelson'. I've used sounds like but it given so many return and the return have far distance with test word. Also I have implemented it with traditional way, but the searching running slow, I compare some data (from excel, the number of data 200 record) with database record about 600.000 record.Does anyone have idea with my problem?Or have implement this case? Thank you for helping..
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As you haven't said what the database is, I'm going to assume you are talking about SQL Server. Most "real" databases provide a SOUNDEX[^] function which can be used to do this form of matching.
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