Adding records with referential integrity
in [Tables]
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From: atledreier on 29 Apr 2010 04:51 I have a few tables in my database, all 1 to 1 with the master table. I have a query that gather much of the data into one large datasheet.The problem is I cannot add records through this query. I get a message that I need a related record in the child table for it to work. Am I right in assuming I need to add the record in the master database first, then the inegrity check will create the record inthe child databases, and THEN I can add data through my datasheet?
From: BruceM via AccessMonster.com on 29 Apr 2010 09:19 A 1 to 1 relationship is unusual, as there can be only one child record for each parent record. A search for subclass or subclassing should produce some more information Without knowing anything about how your database is put together or what it is used for it is almost impossible to offer specific suggestions. In general you do not assemble several tables into a single query for data entry purposes. For one thing, such queries are often read- only. In other cases (such as yours) there may be data integrity issues that cannot be resolved. As a point of terminology, "master database" is not especially meaningful. I assume you mean the main table. If so, you are correct that you need a parent record before you can have a child (related) record. However, it is incorrect that "the inegrity check will create the record in the child {tables}". The integrity check is just that: a check. It does not by itself perform actions. For adding child records, a form/subform is the typical route. A better understanding of databases in general and Access in particular may be of value: Jeff Conrad's resources page: http://www.accessmvp.com/JConrad/accessjunkie/resources.html The Access Web resources page: http://www.mvps.org/access/resources/index.html Roger Carlson's tutorials, samples and tips: http://www.rogersaccesslibrary.com/ A free tutorial written by Crystal: http://allenbrowne.com/casu-22.html A video how-to series by Crystal: http://www.YouTube.com/user/LearnAccessByCrystal MVP Allen Browne's tutorials: http://allenbrowne.com/links.html#Tutorials atledreier wrote: >I have a few tables in my database, all 1 to 1 with the master table. > >I have a query that gather much of the data into one large >datasheet.The problem is I cannot add records through this query. >I get a message that I need a related record in the child table for it >to work. > >Am I right in assuming I need to add the record in the master database >first, then the inegrity check will create the record inthe child >databases, and THEN I can add data through my datasheet? -- Message posted via http://www.accessmonster.com
From: John W. Vinson on 29 Apr 2010 12:43 On Thu, 29 Apr 2010 01:51:32 -0700 (PDT), atledreier <atledreier(a)gmail.com> wrote: >I have a few tables in my database, all 1 to 1 with the master table. That's an *extremely* unusual design. What are these tables? Why do you need one to one relationships? Are you perhaps trying to get around the 255 field limit? If so, you are on the wrong track! >I have a query that gather much of the data into one large >datasheet.The problem is I cannot add records through this query. >I get a message that I need a related record in the child table for it >to work. I'm guessing that the messages is that you need a related record in the PARENT table, not the child? >Am I right in assuming I need to add the record in the master database >first, then the inegrity check will create the record inthe child >databases, and THEN I can add data through my datasheet? The integrity check will *prevent* the addition of an invalid record but no, it will not automagically create a new child record. I think you're really on the wrong track, and probably are "committing spreadsheet". Please post a description of your tables; I'm sure there's a better way to accomplish what you want done. -- John W. Vinson [MVP]
From: atledreier on 30 Apr 2010 02:52 Thank you guys. I'll give you more details. I am in the design phase of a project, and my client wants me to import all my data when all is as-built. My client has a database for all his needed info, so I just used that database structure as a basis for my design. I also added some new tables for design specific data, and some other stuff that won't go to my client. There is the master tag table. This holds the main list of records. Then supporting tables to give more information about different kinds of tags. First, the tables: I've not listed all the fields, but the most relevant ones. Tag: *Tag Description Tag_Cat (category) Function_code .... Tag_misc: *tag manufacturer misc fields.... Tag_Failure_Mode: *tag Fail_code Fail_mode ..... Tag_Format_in/_br_/te *tag cal_low cal_high IP-grade ..... The tag_misc table is 1 to 1. All tags should have information in the tag_misc table. I know I then should have all that information in one table, but since the original client structure needs to be maintained I chose that design. And this has worked for a while, so I thought it'd still work. The tag_failure_mode table should contain data for most tags, but not all. I chose to have a record in there for all tags regardless, as i thought that may be easier to maintain. This is based on the tag! function_code field. The tag_format table should have data for tags of certain tag!tag_cat values (br, in and te type tags). Once again, most of my tags are in this category, so I chose to have all tags in this table too. So I have used a query to gather up all the relevant fields for my users (they are conservative and like their big excel-like datasheets) in one big list. My client made a change in his underlying database recently, so I thought I'd take the opportunity to re-work my database as well. trying to get rid of the big queries and relying more on forms, and also finally linking the database (we've all been working on the same file up until now). So after these changes I get the message that a relevant record needs to exist in the CHILD database, the Tag_failure_mode table in my instance. If it is like you say then I find it strange that this has worked before, really. I see how it would work like you say, but then how did it work this long? It was after I linked the database and added the Tag_failure_mode table it stopped working. I also made many other changes, so I can't tell what I did to break it. Any tips on how to restructure or set stuff up to make this as smooth as possible? - Atle On 29 apr, 18:43, John W. Vinson <jvinson(a)STOP_SPAM.WysardOfInfo.com> wrote: > On Thu, 29 Apr 2010 01:51:32 -0700 (PDT), atledreier <atledre...(a)gmail.com> > wrote: > > >I have a few tables in my database, all 1 to 1 with the master table. > > That's an *extremely* unusual design. What are these tables? Why do you need > one to one relationships? Are you perhaps trying to get around the 255 field > limit? If so, you are on the wrong track! > > >I have a query that gather much of the data into one large > >datasheet.The problem is I cannot add records through this query. > >I get a message that I need a related record in the child table for it > >to work. > > I'm guessing that the messages is that you need a related record in the PARENT > table, not the child? > > >Am I right in assuming I need to add the record in the master database > >first, then the inegrity check will create the record inthe child > >databases, and THEN I can add data through my datasheet? > > The integrity check will *prevent* the addition of an invalid record but no, > it will not automagically create a new child record. > > I think you're really on the wrong track, and probably are "committing > spreadsheet". Please post a description of your tables; I'm sure there's a > better way to accomplish what you want done. > -- > > John W. Vinson [MVP]
From: BruceM via AccessMonster.com on 30 Apr 2010 07:35
If there could be more than one record for Tag_Misc, Tag_Failure_Mode, and Tag_Format, those tables need to one-to-many. If they are one-to-one there can be only one Tag_Misc record for each Tag. In the Relationships window, one-to-many will appear (in Access 2003 and earlier, anyhow) with a 0 on one end of the relationship line, and an infinity symbol on the other. The problem I see is that it seems you are attempting to link the primary keys of your tables. Using Tag_Misc as an example, you should have: tblTag: * TagID Description Tag_Cat (category) Function_code tblTag_misc *Tag_miscID TagID (linking field to tblTag) manufacturer misc fields.... It may be possible under some specific circumstances to link the PK of one table to the PK of another for a one-to-one. If so, it would work only if the PK field of the linked table is not autonumber. I'm not sure if it will work even in that case, as on the rare occasions I have used one-to-one I have designed the table as if for one-to-many, but with a unique index on the linking field. You can set the Required property of the linking field to Yes, but that only means (unless I am missing something) that if there is a record it must have a value in that field. If you want to require Tag_misc records for each Tag record I think you will need to enforce that at the form level, or at least in some way other than requiring a value in that field. Form/subform is the best way to set this up. It would be possible to append values in other ways, but for day-to-day data entry it is unlikely it would make much sense to take that approach. A form based on a query including several table may not be updatable. For more: http://allenbrowne.com/ser-61.html On another note, I would not use Tag as a table or field name, as it is a property of forms, reports, and controls. If you use it you would have to enclose it in square brackets, or you could get some unexpected results. I have suggested tblTag as the table name, and TagID as the field name, but you can choose what you like. For more on Reserved words: http://www.accessmvp.com/JConrad/accessjunkie/resources.html#ReservedWords I have found Allen Browne's Problem names and reserved words in Access to be especially helpful. atledreier wrote: >Thank you guys. I'll give you more details. > >I am in the design phase of a project, and my client wants me to >import all my data when all is as-built. My client has a database for >all his needed info, so I just used that database structure as a basis >for my design. I also added some new tables for design specific data, >and some other stuff that won't go to my client. > >There is the master tag table. This holds the main list of records. >Then supporting tables to give more information about different kinds >of tags. > >First, the tables: I've not listed all the fields, but the most >relevant ones. > >Tag: >*Tag >Description >Tag_Cat (category) >Function_code >... > >Tag_misc: >*tag >manufacturer >misc fields.... > >Tag_Failure_Mode: >*tag >Fail_code >Fail_mode >.... > >Tag_Format_in/_br_/te >*tag >cal_low >cal_high >IP-grade >.... > >The tag_misc table is 1 to 1. All tags should have information in the >tag_misc table. I know I then should have all that information in one >table, but since the original client structure needs to be maintained >I chose that design. And this has worked for a while, so I thought >it'd still work. > >The tag_failure_mode table should contain data for most tags, but not >all. I chose to have a record in there for all tags regardless, as i >thought that may be easier to maintain. This is based on the tag! >function_code field. > >The tag_format table should have data for tags of certain tag!tag_cat >values (br, in and te type tags). Once again, most of my tags are in >this category, so I chose to have all tags in this table too. > >So I have used a query to gather up all the relevant fields for my >users (they are conservative and like their big excel-like datasheets) >in one big list. >My client made a change in his underlying database recently, so I >thought I'd take the opportunity to re-work my database as well. >trying to get rid of the big queries and relying more on forms, and >also finally linking the database (we've all been working on the same >file up until now). >So after these changes I get the message that a relevant record needs >to exist in the CHILD database, the Tag_failure_mode table in my >instance. >If it is like you say then I find it strange that this has worked >before, really. I see how it would work like you say, but then how did >it work this long? It was after I linked the database and added the >Tag_failure_mode table it stopped working. I also made many other >changes, so I can't tell what I did to break it. > >Any tips on how to restructure or set stuff up to make this as smooth >as possible? > >- Atle > >On 29 apr, 18:43, John W. Vinson <jvinson(a)STOP_SPAM.WysardOfInfo.com> >wrote: > >> >I have a few tables in my database, all 1 to 1 with the master table. >> >[quoted text clipped - 23 lines] >> >> John W. Vinson [MVP] -- Message posted via AccessMonster.com http://www.accessmonster.com/Uwe/Forums.aspx/access-tablesdbdesign/201004/1 |