Question: What was this major international multi-sport event, with the opening ceremonies taking place on 27 July, and in which the South African field hockey player Bernadette Coston competed for the outh Africa women's national field hockey team?

Context articles: Sulette Damons
Marc Lammers
2012 Summer Olympics
Dirkie Chamberlain
Tyla Flexman
Bernadette Coston
Ashlee Wells
Kate Woods (field hockey)
Nicolene Terblanche
Illse Davids

Sulette Damons (born 30 October 1989) is a South African field hockey player.
 At the 2012 Summer Olympics she competed with the South Africa women's national field hockey team in the women's tournament.
Marc Lammers (born March 15, 1969 in Oss, North Brabant) is a former field hockey player and head coach.
 In the past, he led the Spanish women's national field hockey team from 1999 to 2000 and the Dutch women's national field hockey team from 2000 to 2008.
 Under his guidance the Dutch team won the silver medal at the 2004 Summer Olympics in Athens, Greece and gold at the 2008 Summer Olympics in Beijing, China.
 Later he also coached the Belgian men's national field hockey team until 2014, with whom he became European vice-champion.
 As a player, he earned five caps for the Men's Squad.
 Lammers played for sixteen years in the Netherlands' first division named "Hoofdklasse", with HC Den Bosch, HC Tilburg and Oranje Zwart.
The 2012 Summer Olympics, formally the Games of the XXX Olympiad and commonly known as London 2012, was a major international multi-sport event celebrated in the tradition of the Olympic Games, as governed by the International Olympic Committee (IOC).
 It took place in London and to a lesser extent across the United Kingdom from 25 July to 12 August 2012.
 The first event, the group stage in women's football began on 25 July at the Millennium Stadium in Cardiff, followed by the opening ceremonies on 27 July.
 10,768 athletes from 204 National Olympic Committees (NOCs) participated.
Dirkie Chamberlain (born 3 November 1986, Pretoria) is a South African field hockey player.
 At the 2012 Summer Olympics she competed with the South Africa women's national field hockey team in the women's tournament.
 She has also competed at the 2010 and 2014 Commonwealth Games.
Tyla Flexman (born July 16, 1986 in New Westminster, British Columbia) is a field hockey player from Canada who played midfield for the Canadian Women's National Field Hockey Team from 2004-2012.
 She started playing field hockey in grade 8 at Sir Winston Churchill Secondary School (Vancouver) and played for the Junior Women's National Field Hockey Team from 2004–2005, competing in the Junior Pan Am Cup and Junior World Cup in 2005.
 In 2008, she played her 5th and final year with the University of British Columbia and was selected as the National Gail Wilson Award winner as well as Canada West Player of the Year while completing her degree in Human Kinetics.
 She was selected to the Senior Women's National Field Hockey Team in 2008 and played center midfield for the team (#18) until her retirement in 2012.
 During that time she played in the 2010 Commonwealth Games, 2011 Pan American Games, and in two FIH Champions Challenge II Tournaments.
 In 2012, she won the BC Female Field Hockey Player of the Year.
 Following her retirement she joined Fortius Sport & Health as a Coordinator for Partnerships and Programs.
Bernadette Coston (born 17 August 1989) is a South African field hockey player.
 At the 2012 Summer Olympics she competed with the South Africa women's national field hockey team in the women's tournament.
Ashlee Wells (born 1 August 1989 in Moe, Victoria) is an Australian field hockey player who plays as a goalkeeper.
 Wells was a member of the Australia women's national field hockey team that were defeated by the Netherlands women's national field hockey team in the final of the 2014 Women's Hockey World Cup.
 As of October 2015, Wells has 52 caps to her name.
 She debuted for Australia in October, 2011.
 Her former club is Churchill HC, Latrobe, Victoria.
 Wells’ mother influenced her to pick up a hockey stick at age five.
 After working for Hockey Victoria, Wells decided to join the national squad in Perth in 2011.
 Some recent competitions Wells participated in include the 2015 World League, 2014 Champions Trophy, 2014 World Cup, 2013 World League and the 2013 Oceania Cup.
 She was also the reserve Goalkeeper for the London 2012 Olympics, while her very first major international tournament was the Junior World Cup in 2009.
Kate Woods (born 11 October 1981) is a South African field hockey player.
 At the 2012 Summer Olympics she competed with the South Africa women's national field hockey team in the women's tournament.
Nicolene Terblanche (born 22 February 1988, Groblersdal, Sekhukhune) is a South African field hockey player.
 At the 2012 Summer Olympics she competed with the South Africa women's national field hockey team in the women's tournament.
Illse Davids (born 26 March 1987, Cape Town) is a South African field hockey player.
 At the 2012 Summer Olympics she competed with the South Africa women's national field hockey team in the women's tournament.
 She studied at the University of North Carolina and played for their hockey team.