was any hagiography written for the saint?
Yes,the "Buchedd Dewi" ("Life of David").
Saint David
Many of the traditional tales about David are found in the "Buchedd Dewi" ("Life of David"), a hagiography written by Rhygyfarch in the late 11th century. 
marina and the diamonds electra heart album songs "Primadonna", "Power & Control", "How to Be a Heartbreaker", "Lonely Hearts " and others. which band has created this album? Not by a band , but the singer Marina Diamandis created this. were any of the songs from this album, performed at any of her tours? Yes, "How to Be a Heartbreaker" was performed on The Lonely Hearts Club Tour at the HMV Institute in Birmingham. what was the purpose of this club tour? To promote her new album. where was the singer born? Brynmawr. is it a city? It is a market town, community and electoral ward. can we see any interesting places there? Yes, a nature reserve named Parc Nant y Waun. what do they do for their economic stability? There are many traditional, family oriented and independently run shops, along with many artisan food producing units. can you name any food from the town? Pickle and Pizza . where is the town located? In Blaenau Gwent, Wales, above the South West Valleys. did the wales valley faced any decline? Yes, it began after 1947. what culture do they follow? The Welsh culture. can you specify any of their tradition? The patron saint of Wales is Saint David, "Dewi Sant" in Welsh. who is the saint mentioned above? He was a Welsh bishop of Mynyw during the 6th century. what was his connection to glastonbury? According to William of Malmesbury , The saint commissioned an extension to be built to the Glastonbury Abbey.
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Saint David [SEP] Hagiography
Many of the traditional tales about David are found in the "Buchedd Dewi" ("Life of David"), a hagiography written by Rhygyfarch in the late 11th century. Rhygyfarch claimed it was based on documents found in the cathedral archives. Modern historians are sceptical of some of its claims: one of Rhygyfarch's aims was to establish some independence for the Welsh church, which had refused the Roman rite until the 8th century and now sought a metropolitan status equal to that of Canterbury. (This may apply to the supposed pilgrimage to Jerusalem where he is said to have been anointed as an archbishop by the patriarch.) The tradition that he was born at Henfynyw (Vetus-Menevia) in Ceredigion is not improbable.