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#11
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AutoNumber Question
Good point. But does this mean that setting the No Duplicates option on a
particular field only applies if that field is a Primary Key? I was under the impression that it you can select No Dups for any Field. So, with the SSN or VIN anaolgies, couldnt one still ensure the uniqueness of them, even if they werent the PriKey? And still use the AutoNumber option for the Primary? "BruceM" wrote in message ... I would like to point out that a primary key does not need to be meaningless to the user. A sequential number such as 000001, 000002, etc. may be used for invoice numbers or the like. I don't see any reason why that number can't be the PK. There are legal reasons why SSN should not be widely available in a database, as it would be if it was part of relationships. However, I would think an employer would want to know if the number is not unique. If John Smith leaves the company, and five years later Jill Jones shows up with John Smith's SSN, I expect it would be a real mess for a company that simply ignores the duplication. A VIN as a PK could get a bit murky for an insurance company or the DMV if a vehicle changes hands, but I expect either entity would want to know if a VIN is being reused. A VIN could make sense as a PK in some situations. Uniqueness is one thing; suitablility for use as a PK is another. There are a lot of possible circumstances, each of which needs to be considered separately. "accessquestions" wrote in message ... understood. I actually thought of that after I posted. Just goes to show that it really takes an analytical mind to perfect the concepts of relational databases. A VIN, like you state, serves a purpose, and is an attribute (an important one) of a vehicle. Not just a random number to identify it's uniqueness in a database. If it were a Database containing vehicle information, the VIN would not be a proper number to use a primary key identifier either (just like a SSN), but instead a value relating to another value. And even then, a random number, such as Aceess' AutoNumber should be used for the system to identify it and its uniqueness. This dialogue was very educational for me as it relates to what I have read many times on the boards ut it all on paper first", and, "determine all information to be stored in the database and its relations to other tables" before creating them. If this was done, I would know that the SSN and VIN Numbers were not suitable candidates for a Unique Identifier. Point Taken ! Thanks for all your insight ,as usual VL "tina" wrote in message news well, glad i could help. but i have to point out that the VIN analogy is not apt. a VIN is not just a collections of numbers/letters, it is a very specific code that identifies manufacturer, make and model of vehicle, model year of vehicle, sometimes where the vehicle was built, sometimes engine size, sometimes maximum payload for trucks, and other data - as well as the last 4 to 6 digits that are unique to a specific vehicle that is otherwise identical to many other vehicles in all those other respects. so a VIN has meaning separate from any tracking database that stores it, and it must often be seen and used directly by people - such as manufacturers, owners, insurers, DMVs. an Autonumber primary key, on the other hand, has no meaning outside of the database where the data is stored, and no meaning within the database, except to the software - and it absolutely should *not* be used with the idea of attaching a meaning to it. it also should not be seen by anyone who uses the database, at any time - excepting only that the developer may look at Autonumber values from time to time while building and/or troubleshooting the database. hth "accessquestions" wrote in message ... good point. the Auto Number is sort like a VIN on a car, you rarely have to see it, but its there and its serving a purpose,, and nobody committs it to memory, if they would it would just confuse them. you convinced me, im an auto number guy from now on. thanks "tina" wrote in message ... well, personally, i would not use the SSN as a primary key, for 2 reasons. first, SSNs are unfortunately not unique; there are many, many duplicates floating around out there. of course, only one person is using a specific SSN *legally*, but unless you want to get into tracking down fraudulent use... second, if you use the SSN as primary key, you'll have it populating multiple tables, potentially scattered all over your database. again, personally, i would safeguard an SSN the same way i would a credit card number, in my database; put it in one place, and one place only, so it's easier to protect by whatever means you use to secure proprietary data. having said all that, there's no reason you can't use an Autonumber as the primary key field for your employee table *as long as it is a value the has no meaning to anyone, only to Access*. your user should never see an Autonumber primary key, or use it directly to search for a record in the table. don't confuse how your *user* finds a certain record in a table with how *Access* identifies each record in a table. you can easily use an Autonumber primary key and still allow your user to seach for an employee record using the person's SSN. hth "accessquestions" wrote in message ... Hello, As far as a Primary Key is concerned (for an Employee Table) I have read numerous times on the boards NOT to use the Auto Number feature, I'm not sure exactly why, although I could see where the random number can confuse some. Would anyone recommend using a SSN instead? It will be unique, and it will serve as a good reference to the employee. Any thoughts of why or why not? Thanks Again ! VL |
#12
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AutoNumber Question
comments inline.
"accessquestions" wrote in message ... Good point. But does this mean that setting the No Duplicates option on a particular field only applies if that field is a Primary Key? no. I was under the impression that it you can select No Dups for any Field. that is correct. So, with the SSN or VIN anaolgies, couldnt one still ensure the uniqueness of them, even if they werent the PriKey? well, to be more precise, you can set a unique index on any field to ensure that no duplicate values can be entered in the field. you may have duplicate *data*, but you can't enter that duplicate data in a field with a Unique index setting. And still use the AutoNumber option for the Primary? correct. "BruceM" wrote in message ... I would like to point out that a primary key does not need to be meaningless to the user. A sequential number such as 000001, 000002, etc. may be used for invoice numbers or the like. I don't see any reason why that number can't be the PK. There are legal reasons why SSN should not be widely available in a database, as it would be if it was part of relationships. However, I would think an employer would want to know if the number is not unique. If John Smith leaves the company, and five years later Jill Jones shows up with John Smith's SSN, I expect it would be a real mess for a company that simply ignores the duplication. A VIN as a PK could get a bit murky for an insurance company or the DMV if a vehicle changes hands, but I expect either entity would want to know if a VIN is being reused. A VIN could make sense as a PK in some situations. Uniqueness is one thing; suitablility for use as a PK is another. There are a lot of possible circumstances, each of which needs to be considered separately. "accessquestions" wrote in message ... understood. I actually thought of that after I posted. Just goes to show that it really takes an analytical mind to perfect the concepts of relational databases. A VIN, like you state, serves a purpose, and is an attribute (an important one) of a vehicle. Not just a random number to identify it's uniqueness in a database. If it were a Database containing vehicle information, the VIN would not be a proper number to use a primary key identifier either (just like a SSN), but instead a value relating to another value. And even then, a random number, such as Aceess' AutoNumber should be used for the system to identify it and its uniqueness. This dialogue was very educational for me as it relates to what I have read many times on the boards ut it all on paper first", and, "determine all information to be stored in the database and its relations to other tables" before creating them. If this was done, I would know that the SSN and VIN Numbers were not suitable candidates for a Unique Identifier. Point Taken ! Thanks for all your insight ,as usual VL "tina" wrote in message news well, glad i could help. but i have to point out that the VIN analogy is not apt. a VIN is not just a collections of numbers/letters, it is a very specific code that identifies manufacturer, make and model of vehicle, model year of vehicle, sometimes where the vehicle was built, sometimes engine size, sometimes maximum payload for trucks, and other data - as well as the last 4 to 6 digits that are unique to a specific vehicle that is otherwise identical to many other vehicles in all those other respects. so a VIN has meaning separate from any tracking database that stores it, and it must often be seen and used directly by people - such as manufacturers, owners, insurers, DMVs. an Autonumber primary key, on the other hand, has no meaning outside of the database where the data is stored, and no meaning within the database, except to the software - and it absolutely should *not* be used with the idea of attaching a meaning to it. it also should not be seen by anyone who uses the database, at any time - excepting only that the developer may look at Autonumber values from time to time while building and/or troubleshooting the database. hth "accessquestions" wrote in message ... good point. the Auto Number is sort like a VIN on a car, you rarely have to see it, but its there and its serving a purpose,, and nobody committs it to memory, if they would it would just confuse them. you convinced me, im an auto number guy from now on. thanks "tina" wrote in message ... well, personally, i would not use the SSN as a primary key, for 2 reasons. first, SSNs are unfortunately not unique; there are many, many duplicates floating around out there. of course, only one person is using a specific SSN *legally*, but unless you want to get into tracking down fraudulent use... second, if you use the SSN as primary key, you'll have it populating multiple tables, potentially scattered all over your database. again, personally, i would safeguard an SSN the same way i would a credit card number, in my database; put it in one place, and one place only, so it's easier to protect by whatever means you use to secure proprietary data. having said all that, there's no reason you can't use an Autonumber as the primary key field for your employee table *as long as it is a value the has no meaning to anyone, only to Access*. your user should never see an Autonumber primary key, or use it directly to search for a record in the table. don't confuse how your *user* finds a certain record in a table with how *Access* identifies each record in a table. you can easily use an Autonumber primary key and still allow your user to seach for an employee record using the person's SSN. hth "accessquestions" wrote in message ... Hello, As far as a Primary Key is concerned (for an Employee Table) I have read numerous times on the boards NOT to use the Auto Number feature, I'm not sure exactly why, although I could see where the random number can confuse some. Would anyone recommend using a SSN instead? It will be unique, and it will serve as a good reference to the employee. Any thoughts of why or why not? Thanks Again ! VL |
#13
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AutoNumber Question
alrighty then,
thanks Tina! "tina" wrote in message ... comments inline. "accessquestions" wrote in message ... Good point. But does this mean that setting the No Duplicates option on a particular field only applies if that field is a Primary Key? no. I was under the impression that it you can select No Dups for any Field. that is correct. So, with the SSN or VIN anaolgies, couldnt one still ensure the uniqueness of them, even if they werent the PriKey? well, to be more precise, you can set a unique index on any field to ensure that no duplicate values can be entered in the field. you may have duplicate *data*, but you can't enter that duplicate data in a field with a Unique index setting. And still use the AutoNumber option for the Primary? correct. "BruceM" wrote in message ... I would like to point out that a primary key does not need to be meaningless to the user. A sequential number such as 000001, 000002, etc. may be used for invoice numbers or the like. I don't see any reason why that number can't be the PK. There are legal reasons why SSN should not be widely available in a database, as it would be if it was part of relationships. However, I would think an employer would want to know if the number is not unique. If John Smith leaves the company, and five years later Jill Jones shows up with John Smith's SSN, I expect it would be a real mess for a company that simply ignores the duplication. A VIN as a PK could get a bit murky for an insurance company or the DMV if a vehicle changes hands, but I expect either entity would want to know if a VIN is being reused. A VIN could make sense as a PK in some situations. Uniqueness is one thing; suitablility for use as a PK is another. There are a lot of possible circumstances, each of which needs to be considered separately. "accessquestions" wrote in message ... understood. I actually thought of that after I posted. Just goes to show that it really takes an analytical mind to perfect the concepts of relational databases. A VIN, like you state, serves a purpose, and is an attribute (an important one) of a vehicle. Not just a random number to identify it's uniqueness in a database. If it were a Database containing vehicle information, the VIN would not be a proper number to use a primary key identifier either (just like a SSN), but instead a value relating to another value. And even then, a random number, such as Aceess' AutoNumber should be used for the system to identify it and its uniqueness. This dialogue was very educational for me as it relates to what I have read many times on the boards ut it all on paper first", and, "determine all information to be stored in the database and its relations to other tables" before creating them. If this was done, I would know that the SSN and VIN Numbers were not suitable candidates for a Unique Identifier. Point Taken ! Thanks for all your insight ,as usual VL "tina" wrote in message news well, glad i could help. but i have to point out that the VIN analogy is not apt. a VIN is not just a collections of numbers/letters, it is a very specific code that identifies manufacturer, make and model of vehicle, model year of vehicle, sometimes where the vehicle was built, sometimes engine size, sometimes maximum payload for trucks, and other data - as well as the last 4 to 6 digits that are unique to a specific vehicle that is otherwise identical to many other vehicles in all those other respects. so a VIN has meaning separate from any tracking database that stores it, and it must often be seen and used directly by people - such as manufacturers, owners, insurers, DMVs. an Autonumber primary key, on the other hand, has no meaning outside of the database where the data is stored, and no meaning within the database, except to the software - and it absolutely should *not* be used with the idea of attaching a meaning to it. it also should not be seen by anyone who uses the database, at any time - excepting only that the developer may look at Autonumber values from time to time while building and/or troubleshooting the database. hth "accessquestions" wrote in message ... good point. the Auto Number is sort like a VIN on a car, you rarely have to see it, but its there and its serving a purpose,, and nobody committs it to memory, if they would it would just confuse them. you convinced me, im an auto number guy from now on. thanks "tina" wrote in message ... well, personally, i would not use the SSN as a primary key, for 2 reasons. first, SSNs are unfortunately not unique; there are many, many duplicates floating around out there. of course, only one person is using a specific SSN *legally*, but unless you want to get into tracking down fraudulent use... second, if you use the SSN as primary key, you'll have it populating multiple tables, potentially scattered all over your database. again, personally, i would safeguard an SSN the same way i would a credit card number, in my database; put it in one place, and one place only, so it's easier to protect by whatever means you use to secure proprietary data. having said all that, there's no reason you can't use an Autonumber as the primary key field for your employee table *as long as it is a value the has no meaning to anyone, only to Access*. your user should never see an Autonumber primary key, or use it directly to search for a record in the table. don't confuse how your *user* finds a certain record in a table with how *Access* identifies each record in a table. you can easily use an Autonumber primary key and still allow your user to seach for an employee record using the person's SSN. hth "accessquestions" wrote in message ... Hello, As far as a Primary Key is concerned (for an Employee Table) I have read numerous times on the boards NOT to use the Auto Number feature, I'm not sure exactly why, although I could see where the random number can confuse some. Would anyone recommend using a SSN instead? It will be unique, and it will serve as a good reference to the employee. Any thoughts of why or why not? Thanks Again ! VL |
#14
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AutoNumber Question
you're welcome
"accessquestions" wrote in message ... alrighty then, thanks Tina! "tina" wrote in message ... comments inline. "accessquestions" wrote in message ... Good point. But does this mean that setting the No Duplicates option on a particular field only applies if that field is a Primary Key? no. I was under the impression that it you can select No Dups for any Field. that is correct. So, with the SSN or VIN anaolgies, couldnt one still ensure the uniqueness of them, even if they werent the PriKey? well, to be more precise, you can set a unique index on any field to ensure that no duplicate values can be entered in the field. you may have duplicate *data*, but you can't enter that duplicate data in a field with a Unique index setting. And still use the AutoNumber option for the Primary? correct. "BruceM" wrote in message ... I would like to point out that a primary key does not need to be meaningless to the user. A sequential number such as 000001, 000002, etc. may be used for invoice numbers or the like. I don't see any reason why that number can't be the PK. There are legal reasons why SSN should not be widely available in a database, as it would be if it was part of relationships. However, I would think an employer would want to know if the number is not unique. If John Smith leaves the company, and five years later Jill Jones shows up with John Smith's SSN, I expect it would be a real mess for a company that simply ignores the duplication. A VIN as a PK could get a bit murky for an insurance company or the DMV if a vehicle changes hands, but I expect either entity would want to know if a VIN is being reused. A VIN could make sense as a PK in some situations. Uniqueness is one thing; suitablility for use as a PK is another. There are a lot of possible circumstances, each of which needs to be considered separately. "accessquestions" wrote in message ... understood. I actually thought of that after I posted. Just goes to show that it really takes an analytical mind to perfect the concepts of relational databases. A VIN, like you state, serves a purpose, and is an attribute (an important one) of a vehicle. Not just a random number to identify it's uniqueness in a database. If it were a Database containing vehicle information, the VIN would not be a proper number to use a primary key identifier either (just like a SSN), but instead a value relating to another value. And even then, a random number, such as Aceess' AutoNumber should be used for the system to identify it and its uniqueness. This dialogue was very educational for me as it relates to what I have read many times on the boards ut it all on paper first", and, "determine all information to be stored in the database and its relations to other tables" before creating them. If this was done, I would know that the SSN and VIN Numbers were not suitable candidates for a Unique Identifier. Point Taken ! Thanks for all your insight ,as usual VL "tina" wrote in message news well, glad i could help. but i have to point out that the VIN analogy is not apt. a VIN is not just a collections of numbers/letters, it is a very specific code that identifies manufacturer, make and model of vehicle, model year of vehicle, sometimes where the vehicle was built, sometimes engine size, sometimes maximum payload for trucks, and other data - as well as the last 4 to 6 digits that are unique to a specific vehicle that is otherwise identical to many other vehicles in all those other respects. so a VIN has meaning separate from any tracking database that stores it, and it must often be seen and used directly by people - such as manufacturers, owners, insurers, DMVs. an Autonumber primary key, on the other hand, has no meaning outside of the database where the data is stored, and no meaning within the database, except to the software - and it absolutely should *not* be used with the idea of attaching a meaning to it. it also should not be seen by anyone who uses the database, at any time - excepting only that the developer may look at Autonumber values from time to time while building and/or troubleshooting the database. hth "accessquestions" wrote in message ... good point. the Auto Number is sort like a VIN on a car, you rarely have to see it, but its there and its serving a purpose,, and nobody committs it to memory, if they would it would just confuse them. you convinced me, im an auto number guy from now on. thanks "tina" wrote in message ... well, personally, i would not use the SSN as a primary key, for 2 reasons. first, SSNs are unfortunately not unique; there are many, many duplicates floating around out there. of course, only one person is using a specific SSN *legally*, but unless you want to get into tracking down fraudulent use... second, if you use the SSN as primary key, you'll have it populating multiple tables, potentially scattered all over your database. again, personally, i would safeguard an SSN the same way i would a credit card number, in my database; put it in one place, and one place only, so it's easier to protect by whatever means you use to secure proprietary data. having said all that, there's no reason you can't use an Autonumber as the primary key field for your employee table *as long as it is a value the has no meaning to anyone, only to Access*. your user should never see an Autonumber primary key, or use it directly to search for a record in the table. don't confuse how your *user* finds a certain record in a table with how *Access* identifies each record in a table. you can easily use an Autonumber primary key and still allow your user to seach for an employee record using the person's SSN. hth "accessquestions" wrote in message ... Hello, As far as a Primary Key is concerned (for an Employee Table) I have read numerous times on the boards NOT to use the Auto Number feature, I'm not sure exactly why, although I could see where the random number can confuse some. Would anyone recommend using a SSN instead? It will be unique, and it will serve as a good reference to the employee. Any thoughts of why or why not? Thanks Again ! VL |
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