The most comprehensive family history database for Derry/Londonderry was built up by Derry Genealogy which can be accessed at http://www.derry.rootsireland.ie
. This database contains the bulk of pre-1922 civil birth and marriage registers for the city and county of Derry, the early baptismal and marriage registers of 85 churches, gravestone inscriptions from 117 graveyards, and census substitutes and census returns dating from 1628 to 1921.
Although RootsIreland is the largest online source of Irish church register transcripts, it must be emphasised that a failure to find any relevant birth/marriage entries in this database (or indeed any of the 'big' Irish databases) doesn't mean that the events you are looking for didn't happen in Ireland. It simply means that they are not recorded in the database; for example, they may be recorded in a record source which doesn't survive for the time period of interest or in a source that has not been computerised.
Your problem, of course, is that it is very difficult to trace ancestors in Ireland in 17th and 18th centuries owing to patchy survival of record sources for this time period. The majority of Irish church registers don’t survive for 18th century. Although Derry Genealogy has computerised the baptismal, marriage and burial registers of 85 churches in County Derry (the earliest being St Columb’s Cathedral in Derry city, dating from 1642),only 8 of them have surviving registers prior to 1800. Hence the birth,marriage and death details of many of our 17th and 18th century ancestors have not survived in a written record source.
Quite often the only realistic strategy in tracing ancestors beyond church registers (which are the building blocks of family history) is to examine surviving land records and census substitutes, often compiled by civil parish, for any references to a surname or given name of interest. There are a number of 17th and 18th century census substitutes (e.g. 1630 Muster Roll, 1663 Hearth Money Rolls, 1740 Protestant Householders Lists, 1766 Religious Census and 1796 Flax Growers Lists) which can be searched to confirm the presence of the family name. The problem with these sources is that they name heads of household only; hence they provide insufficient information to confirm the nature of linkages between named people in these sources. Census substitutes, however, are very useful in confirming the presence of a family name in a particular townland and/or parish, and in providing some insight into the frequency and distribution of surnames.
Many of these 17th and 18th century census substitutes for County Derry can be searched, free of charge on Bill Macafee's website at http://www.billmacafee.com
. These sources will confirm the presence of Rogers households but they will not confirm if and how they are connected to your Rogers ancestors.
For example an examination of the index to the Hearth Money Rolls of 1663 for County Derry, on Bill Macafees website, reveals 8 households with surname Roger/Rodger/Rodgers living in County Derry in the mid-17th century; namely:
Name Parish Townland or Street,Town
James Rodger Aghadowey Gorran
James Rodgers Templemore ShipquayStreet, Londonderry
John Rodger Macosquin Not specified
Nathaniel Rodger Magherafelt Killyfaddy
Robert Roger Magilligan Drummans Upper
Thomas Rodger Aghadowey Gorran
William Roger Tamlaght Finlagan Carrowclare
William Rodgers Templemore Shipquay Street, Londonderry