I am making database for gene bank or seed bank.i have problem in erd of seed bank
Seed bank stores seeds and main modules of seed bank are Germination and Multiplication.
1.A germination test is conducted on seeds by growing them in lab in test tubes.This test tells that how much seeds are alive and how much are dead.Alive seeds are able to grow while dead seeds cannot grow or in other words dead seeds are of no use.Germination percentage refers to the percentage of alive seeds.No of dead and alive seeds are recorded alongwith date of germination and germination percentage

2.Now when quantity of seeds (of a particular crop ) becomes less than 100 or their germination percentage is less than 80 they are sent for multiplication .Seed quantity is increased through multiplication.Date of multiplication of seeds and their quantity after multiplication is recorded and also person who done the multiplication .

The relationship in erd is as follows:
1.SEED are Tested by GERMINATION
2.SEED are Sent for MULTIPLICATION
SEED ,GERMINATION and MULTIPLICATION are entities whereas Tested by and Sent for are gerund or associative entities.My problem is that is that i can not figure out the difference between gerund and entities or what will be their attributes ?what will be different attributes of "Tested by" and Germinationand also for "Sent by" and Multiplication ?
I am not that much good with normalization concepts and mapping of erd
Please help me in recognizing the entities and their attributes

plz help me

It would help if you would post the work you've already done on your ERD.

I'd say not. A SEED BANK may have multiple GERMINATION EVENTs and multiple MULTIPLICATION EVENTs. Tested by and sent for are attributes of these events, indicating who performed the event.

By gerund I guess you mean associative entity? To start, try not to worry about the technicalities, instead focus on figuring out the relationships between the entities you've already described. It can be as simple as figuring out the correct form of these statements for each pair of entities:
* A SEED BANK may|must have one|many GERMINATION EVENTs.
* A GERMINATION EVENT may|must be done on one|many SEED BANKs.

After that, assign your attributes. Does "tested by" describe a SEED BANK or a GERMINATION EVENT?

Hopefully this helps.

Thankyou for replying futurity

Basically seed bank maintains seeds of different crops and SEED is an entity, not SEED BANK.Seeds of a particular are crops are saved and given a unique accession ID and location(row no.,column no. ,rack).These seeds are tested through germination after a certain time period to make a record that how much seeds are alive and how much are dead.Percentage of live seeds is reffered as germination percentage.When this percentage is less than 80% then these seeds are sent for multiplication.Organizations records the germination percentage of seeds,date of germination,employee who has performed germination,temperature maintained,light condition,no. of alive and dead seeds and in case of multiplication records the quantity before multiplication,quantity after multiplication of seeds,employee who multiplied the seeds ,date of sending seeds for multiplication and date when seeds were returned.
GERMINATION and MULTIPLICATION are performed for seeds.Now as far i know i have made the following entities:

>SEED(ACC ID,location,Crop ID)
>CROP(Crop ID,Crop local name,Crop Scientific name)
>EMPLOYEE(E_ID,Name,Rank,Address etc.)
>GERMINATION
>MULTIPLICATION

My problem is with GERMINATION and MULTIPLICATION.By gerund I mean associative entity.When i say that

>SEED are Tested by GERMINATION and
>SEED are Sent for MULTIPLICATION

Here Tested by and Sent for are associative entities or gerunds.
I have made it as follows:

>GERMINATION(G_ID,Temperature,light condition,no. of dead seeds,no. alive seeds,germ %age,need multiplication(y/n))
>Tested by(G_ID,Acc_ID,Emp_ID,Date,Quatitiy)
>MULTIPLICATION(M_ID,Acc_ID,E_ID,quantity received,quantity returned,date)

I dont know that it is right or not and can not understand that what will be attributes of Tested by and what will be attributes of GERMINATION ?Similarly what will be the attributes of Sent for and what will be attributes of MULTIPLICATION.I know that gerund will store date ,quantity and employee ID and this is all the data i gathered from organization.

Okay, but the point is that, as you've described it, a germination test applies to multiple seeds, whatever you want to call it: a "seed bank", "crop", or maybe just "sample". It sounds like the same for multiplication: if the germination rate is too low, the entire sample (or whatever it's called) is sent off so more seeds can be added.

So start off by getting this missing entity modeled (or determining if it's already included in your model), and then associating your germination entity with it. It sounds like this will be a many-to-one relationship: a "sample" (e.g.) can have many germination tests, a germination test is done for one sample at a time.