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#1
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move a primary key to a child
I want to add a child table to my table and using one of the primary
key of the table. For example: MyTable is PKey1 PKey2 PKey3 I would like to move PKey3 out and add a child table as following and remove PKey3 from MyTable: ChildTable as folliwng PKey1 PKey2 PKey3 MyTable will be PKey1 PKey2 I just wonder what will impact in the future like reports, forms, queries, data entries, It seems that I need make a lot of changes for the application. Any suggestions that should I continue to do this change? Your information is great appreciated, |
#2
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move a primary key to a child
I'm not clear on what you mean by "move a primary key"...
In a well-normalized relational design, each table will have a primary key field (or combination of fields). Those serve to uniquely identify the records. If you removed one of a combination of fields that uniquely identifies records, you would no longer have a way to uniquely identify records! According to your description, it appears that your Child table would have the same three primary key fields. That does not compute! If they are "child" records, they will have their own primary key field(s), and will have a foreign key field (multiple fields if the primary key in the "parent" is multiple fields). Could you describe a bit more about what you're trying to do, and perhaps offer example data? More info, please... Regards Jeff Boyce Microsoft Access MVP -- Disclaimer: This author may have received products and services mentioned in this post. Mention and/or description of a product or service herein does not constitute endorsement thereof. Any code or pseudocode included in this post is offered "as is", with no guarantee as to suitability. You can thank the FTC of the USA for making this disclaimer possible/necessary. "inungh" wrote in message ... I want to add a child table to my table and using one of the primary key of the table. For example: MyTable is PKey1 PKey2 PKey3 I would like to move PKey3 out and add a child table as following and remove PKey3 from MyTable: ChildTable as folliwng PKey1 PKey2 PKey3 MyTable will be PKey1 PKey2 I just wonder what will impact in the future like reports, forms, queries, data entries, It seems that I need make a lot of changes for the application. Any suggestions that should I continue to do this change? Your information is great appreciated, |
#3
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move a primary key to a child
On May 12, 2:29*pm, "Jeff Boyce" wrote:
I'm not clear on what you mean by "move a primary key"... In a well-normalized relational design, each table will have a primary key field (or combination of fields). *Those serve to uniquely identify the records. *If you removed one of a combination of fields that uniquely identifies records, you would no longer have a way to uniquely identify records! According to your description, it appears that your Child table would have the same three primary key fields. *That does not compute! *If they are "child" records, they will have their own primary key field(s), and will have a foreign key field (multiple fields if the primary key in the "parent" is multiple fields). Could you describe a bit more about what you're trying to do, and perhaps offer example data? More info, please... Regards Jeff Boyce Microsoft Access MVP -- Disclaimer: This author may have received products and services mentioned in this post. Mention and/or description of a product or service herein does not constitute endorsement thereof. Any code or pseudocode included in this post is offered "as is", with no guarantee as to suitability. You can thank the FTC of the USA for making this disclaimer possible/necessary. "inungh" wrote in message ... I want to add a child table to my table and using one of the primary key of the table. For example: MyTable is PKey1 PKey2 PKey3 I would like to move PKey3 out and add a child table as following and remove PKey3 from MyTable: ChildTable as folliwng PKey1 PKey2 PKey3 MyTable will be PKey1 PKey2 I just wonder what will impact in the future like reports, forms, queries, data entries, It seems that I need make a lot of changes for the application. Any suggestions that should I continue to do this change? Your information is great appreciated,- Hide quoted text - - Show quoted text - Thanks for the message, The application is to create meetings for the users. Original design is to have one subject per meeting, so there is a subjectID in my meeting table and Subject tabls as foreign table. After years running, my client decided to allow multi subjects for the one meeing. I need add a table MeetingSubject as child of the meeting and need remove SubjectID from Meeting table to add in MeetingSubject table. It will be a lot of work to change data structure at this moment. Please advise any other solution for this. Thanks again for the information, |
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