db design to calculate overlap in group membership in time
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From: EHobs on 3 Jun 2010 11:32 Hi all, I am a biologist studying the social structure of birds. I am currently brainstorming ideas for constructing a database that will allow me to easily calculate the number of seconds that one bird is in the same group as another bird. Because group membership changes frequently with birds arriving and departing at different times, and often arriving, departing, and re-arriving on the scale of seconds, I will have many thousands of records. I am trying to determine how to best set up this database before entering all the data. I have 2 goals with this database: 1) I need to find a way that I can streamline data entry. I was thinking 3 columns: ID, time of movement, and whether it is an arrival or departure. Because of the frequent movements and the large number of potential individuals, I need to be able to enter arrivals and departures separately. 2) I need to determine how I am going to calculate the amount of time that any 2 birds at present at the same time. This needs to be able to account for individuals that arrive and depart at different times, and calculate just "shared" time. I think this problem may be somewhat similar to company records of employees hired and fired at different dates, where the amount of time of overlap in employment is calculated. Any help or advice would be greatly appreciated! Thanks, Liz
From: Jeff Boyce on 3 Jun 2010 12:28 Liz If you haven't built a database/application before, and particularly an Access (relational) database/application, there are (at least) four separate learning curves you'll want to consider. Maybe you have already worked your way up some of them... 1. relational database design - if "normalization" isn't familiar, you need to understand it first 2. Access tips/tricks - Access handles things differently than Excel or .... 3. graphical user interface design - you do NOT use the tables in Access for data entry ... that's what the forms are for 4. application development - if you've never built a ... "house", where do you start?! My suggestion is that you put aside some of your "how" questions and focus first on "what". What are the things about which you wish to store (and retrieve) information? These are your "entities". Now, what pieces of information do you want to store about each entity? For example, a person's name and date of birth "belong" to an entity about persons, but do NOT belong to an entity about jobs... Here's a rough idea of how your tables (!entities!) might look if you were building a student registration database (untested, simplistic, for example purposes only): tblPerson PersonID FName LName DOB tblClass ClassID ClassTitle ClassDescription trelEnrollment EnrollmentID PersonID ClassID EnrollmentDate What does your data look like? 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. "EHobs" <u60556(a)uwe> wrote in message news:a8fac2069ea04(a)uwe... > Hi all, > > I am a biologist studying the social structure of birds. I am currently > brainstorming ideas for constructing a database that will allow me to > easily > calculate the number of seconds that one bird is in the same group as > another > bird. Because group membership changes frequently with birds arriving and > departing at different times, and often arriving, departing, and > re-arriving > on the scale of seconds, I will have many thousands of records. I am > trying > to determine how to best set up this database before entering all the > data. I > have 2 goals with this database: > > 1) I need to find a way that I can streamline data entry. I was thinking > 3 > columns: ID, time of movement, and whether it is an arrival or departure. > Because of the frequent movements and the large number of potential > individuals, I need to be able to enter arrivals and departures > separately. > > 2) I need to determine how I am going to calculate the amount of time that > any 2 birds at present at the same time. This needs to be able to account > for > individuals that arrive and depart at different times, and calculate just > "shared" time. > > I think this problem may be somewhat similar to company records of > employees > hired and fired at different dates, where the amount of time of overlap in > employment is calculated. > > Any help or advice would be greatly appreciated! > > Thanks, > > Liz >
From: Steve on 3 Jun 2010 14:32 Hi Liz, I think that the first thing is to answer two questions ... 1. "....one bird is in the same group as another bird" implies that you can identify individual birds. Can you do that and what are the characteristics (fields) that can be used to uniquely identify a bird? 2. What factors (fields) distinguishes one group from another. For example, Bird A and Bird B are together; is that a group? At another spot, Bird C and Bird D are together; is that a group? After a few moments, Bird C and Bird D join Bird A and Bird B. There are now four birds together, is that group AB, Group CD or a new group. Steve santus(a)penn.com "EHobs" <u60556(a)uwe> wrote in message news:a8fac2069ea04(a)uwe... > Hi all, > > I am a biologist studying the social structure of birds. I am currently > brainstorming ideas for constructing a database that will allow me to > easily > calculate the number of seconds that one bird is in the same group as > another > bird. Because group membership changes frequently with birds arriving and > departing at different times, and often arriving, departing, and > re-arriving > on the scale of seconds, I will have many thousands of records. I am > trying > to determine how to best set up this database before entering all the > data. I > have 2 goals with this database: > > 1) I need to find a way that I can streamline data entry. I was thinking > 3 > columns: ID, time of movement, and whether it is an arrival or departure. > Because of the frequent movements and the large number of potential > individuals, I need to be able to enter arrivals and departures > separately. > > 2) I need to determine how I am going to calculate the amount of time that > any 2 birds at present at the same time. This needs to be able to account > for > individuals that arrive and depart at different times, and calculate just > "shared" time. > > I think this problem may be somewhat similar to company records of > employees > hired and fired at different dates, where the amount of time of overlap in > employment is calculated. > > Any help or advice would be greatly appreciated! > > Thanks, > > Liz >
From: EHobs via AccessMonster.com on 4 Jun 2010 12:30 Hi Steve, Thanks for your response. I can identify individual birds by a unique color combination. The field is a 3 letter code corresponding to the 3 colors used to id the bird (ex: bbb is the bird with the blue-blue-blue color combo). I have observations of individuals at one specific location, so any birds observed at that location at the same time are defined as associated. I need to be able to query the db for both group composition at any one time as well as overall shared association time among any 2 individuals. I have not yet entered the data -- I am trying to figure out the best format first to avoid headaches later. I am currently envisioning a table like this (below), but am very open to suggestions! Date Time ID Type (a=arrival, d=departure) 12-Jun 9:01 bbb a 12-Jun 9:02 bbb d 12-Jun 9:02 rrr a 12-Jun 9:02 brr a 12-Jun 9:03 rrr d I would like to run a query that will calculate the amount of time that every bird shared with every other bird (ex from above: bbb shared 0 with rrr, brr; rrr shared 1 with brr; etc). I can have the time of arrival coded in time of day or in number of seconds from the start of observation, which may make calculations simpler. In response to Jeff Boyce's response, I have experience constructing relational databases and queries. I am self-taught, so they usually aren't pretty, but I can usually get things to work. This question with this db that I have is beyond what I have tried to do before. Again, any suggestions would be very appreciated. Thanks, Liz Steve wrote: >Hi Liz, > >I think that the first thing is to answer two questions ... >1. "....one bird is in the same group as another bird" implies that you >can identify individual birds. Can you do that and what are the >characteristics (fields) that can be used to uniquely identify a bird? > >2. What factors (fields) distinguishes one group from another. For >example, Bird A and Bird B are together; is that a group? At another spot, >Bird C and Bird D are together; is that a group? After a few moments, Bird C >and Bird D join Bird A and Bird B. There are now four birds together, is >that group AB, Group CD or a new group. > >Steve >santus(a)penn.com > >> Hi all, >> >[quoted text clipped - 35 lines] >> >> Liz -- Message posted via http://www.accessmonster.com
From: Jeff Boyce on 4 Jun 2010 12:54
The example you provided may not have quite all the information it sounds like you need. Steve asked how you "group" the members/birds. In your example, are all of those birds part of the same group? If so, how do you know/tell Access that fact? 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. "EHobs via AccessMonster.com" <u60556(a)uwe> wrote in message news:a907d7f13e81e(a)uwe... > Hi Steve, > > Thanks for your response. I can identify individual birds by a unique > color > combination. The field is a 3 letter code corresponding to the 3 colors > used > to id the bird (ex: bbb is the bird with the blue-blue-blue color combo). > I > have observations of individuals at one specific location, so any birds > observed at that location at the same time are defined as associated. I > need > to be able to query the db for both group composition at any one time as > well > as overall shared association time among any 2 individuals. I have not yet > entered the data -- I am trying to figure out the best format first to > avoid > headaches later. I am currently envisioning a table like this (below), but > am > very open to suggestions! > > Date Time ID Type (a=arrival, d=departure) > 12-Jun 9:01 bbb a > 12-Jun 9:02 bbb d > 12-Jun 9:02 rrr a > 12-Jun 9:02 brr a > 12-Jun 9:03 rrr d > > I would like to run a query that will calculate the amount of time that > every > bird shared with every other bird (ex from above: bbb shared 0 with rrr, > brr; > rrr shared 1 with brr; etc). I can have the time of arrival coded in time > of > day or in number of seconds from the start of observation, which may make > calculations simpler. > > In response to Jeff Boyce's response, I have experience constructing > relational databases and queries. I am self-taught, so they usually aren't > pretty, but I can usually get things to work. This question with this db > that > I have is beyond what I have tried to do before. Again, any suggestions > would > be very appreciated. > > Thanks, > > Liz > > Steve wrote: >>Hi Liz, >> >>I think that the first thing is to answer two questions ... >>1. "....one bird is in the same group as another bird" implies that you >>can identify individual birds. Can you do that and what are the >>characteristics (fields) that can be used to uniquely identify a bird? >> >>2. What factors (fields) distinguishes one group from another. For >>example, Bird A and Bird B are together; is that a group? At another spot, >>Bird C and Bird D are together; is that a group? After a few moments, Bird >>C >>and Bird D join Bird A and Bird B. There are now four birds together, is >>that group AB, Group CD or a new group. >> >>Steve >>santus(a)penn.com >> >>> Hi all, >>> >>[quoted text clipped - 35 lines] >>> >>> Liz > > -- > Message posted via http://www.accessmonster.com > |