DeleteRecord(Database[], Key, Position, n[, startFrom])

DeleteRecord will scan a database and remove each record that has a field matching the given Key at the given Position. In database parlance, the Position of the key is it's column.
It will remove up to 'n' records or as many it finds that match the request. If you specify a value of 1 for n, then only the first matching record will be erased.
You can use the extra 'startFrom' parameter to skip the first 'startFrom' records of the database.

Return value:
The number of records removed.

Example 1:
We remove all matching records. "mammal" will be found in column '3', the French name has an index of '0' and so on.

sub main


db[0] = makeRecord("chien","dog","1","mammal") $
db[1] = makeRecord("chat","cat","2","mammal") $
db[2] = makeRecord("poisson","fish","3","vertebrate") $
db[3] = makeRecord("escargot","snail","4","invertebrate") $
db[4] = makeRecord("souris","mouse","5","mammal") $
db[5] = makeRecord("perroquet","parrot","6","bird") $
db[6] = makeRecord("dauphin","dolphin","7","mammal") $
db[7] = makeRecord("fleur","flower","8","plant") $

n = getArraySize(db[])
deleteRecord(db[], "mammal", 3, n)

n = getArraySize(db[])
print("New size: ", n, "\n")
for i=0 to n-1
getAllFields(fl[], db[i]$)
print(fl[1]$, " ", fl[3]$, "\n")
end for


end sub

New size: 4.000000
fish vertebrate
snail invertebrate
parrot bird
flower plant

Example 2:
Here, we specify to remove only one field, so only poor doggy will go. :-(

sub main


db[0] = makeRecord("chien","dog","1","mammal") $
db[1] = makeRecord("chat","cat","2","mammal") $
db[2] = makeRecord("poisson","fish","3","vertebrate") $
db[3] = makeRecord("escargot","snail","4","invertebrate") $
db[4] = makeRecord("souris","mouse","5","mammal") $
db[5] = makeRecord("perroquet","parrot","6","bird") $
db[6] = makeRecord("dauphin","dolphin","7","mammal") $
db[7] = makeRecord("fleur","flower","8","plant") $


n = getArraySize(db[])
deleteRecord(db[], "mammal", 3, 1)

n = getArraySize(db[])
print("New size: ", n, "\n")
for i=0 to n-1
getAllFields(fl[], db[i]$)
print(fl[1]$, " ", fl[3]$, "\n")
end for

end sub

New size: 7.000000
cat mammal
fish vertebrate
snail invertebrate
mouse mammal
parrot bird
dolphin mammal
flower plant

Example 3:
Lastly, we specify to remove as many records as possible, however, we start at positon 2, hence saving both dog and cat from oblivion.

sub main

db[0] = makeRecord("chien","dog","1","mammal") $
db[1] = makeRecord("chat","cat","2","mammal") $
db[2] = makeRecord("poisson","fish","3","vertebrate") $
db[3] = makeRecord("escargot","snail","4","invertebrate") $
db[4] = makeRecord("souris","mouse","5","mammal") $
db[5] = makeRecord("perroquet","parrot","6","bird") $
db[6] = makeRecord("dauphin","dolphin","7","mammal") $
db[7] = makeRecord("fleur","flower","8","plant") $


n = getArraySize(db[])
deleteRecord(db[], "mammal", 3, n, 2)

n = getArraySize(db[])
print("New size: ", n, "\n")
for i=0 to n-1
getAllFields(fl[], db[i]$)
print(fl[1]$, " ", fl[3]$, "\n")
end for

end sub

New size: 6.000000
dog mammal
cat mammal
fish vertebrate
snail invertebrate
parrot bird
flower plant