通話アクティビティフィールドのマッピング

本スクリプトは、テキストフィールドとして保存されている従来のタイムゾーン値を、新しい選択リストフィールドへマッピングします。

実行にあたっては、Salesforce Developer Console または Workbench を使用します。なお、Salesforce Developer Console における文字数制限に対応するため、スクリプトは2つのパートに分かれています。各パートでそれぞれ一部のタイムゾーン（サブセット）を順次処理します。

スクリプト内には、以下の2つの変数が定義されています。

• sObjectName：旧タイムゾーン値を新しい値へマッピングする対象のオブジェクト名に合わせて、変数の値を更新します。

• recordLimit：1回のトランザクションで処理する最大レコード数を制限します。

処理対象レコードの抽出条件：Dialpad__Timezone__c フィールドが空（NULL）ではなく、かつ Dialpad__Dialpad_Timezone__c フィールドが空（NULL）であること。

// ============================================================
// PART 1 of 2
// Run Part 1 first, then run Part 2.
// ============================================================
String sObjectName = 'Account';                        // e.g. 'Account', 'Contact', 'Lead'
Integer recordLimit = 200;                             // Max limit 10000, Update as per org configuration 
String sourceField = 'Dialpad__Timezone__c';           // Old Text Field API
String targetField = 'Dialpad__Dialpad_Timezone__c';   // New Picklist Field API 
Map<String, String> tzMap = new Map<String, String>{
'Pacific/Midway' => 'GMT-11:00 - American Samoa, Niue (SST)',
'Pacific/Niue' => 'GMT-11:00 - American Samoa, Niue (SST)',
'Pacific/Pago_Pago' => 'GMT-11:00 - American Samoa, Niue (SST)',
'America/Adak' => 'GMT-10:00 - Hawaii, Tahiti, Cook Islands (HST)',
'Pacific/Honolulu' => 'GMT-10:00 - Hawaii, Tahiti, Cook Islands (HST)',
'Pacific/Johnston' => 'GMT-10:00 - Hawaii, Tahiti, Cook Islands (HST)',
'Pacific/Rarotonga' => 'GMT-10:00 - Hawaii, Tahiti, Cook Islands (HST)',
'Pacific/Tahiti' => 'GMT-10:00 - Hawaii, Tahiti, Cook Islands (HST)',
'Pacific/Marquesas' => 'GMT-09:30 - Marquesas Islands (MART)',
'America/Anchorage' => 'GMT-09:00 - Alaska, Gambier Islands (AKST)',
'America/Juneau' => 'GMT-09:00 - Alaska, Gambier Islands (AKST)',
'America/Metlakatla' => 'GMT-09:00 - Alaska, Gambier Islands (AKST)',
'America/Nome' => 'GMT-09:00 - Alaska, Gambier Islands (AKST)',
'America/Sitka' => 'GMT-09:00 - Alaska, Gambier Islands (AKST)',
'America/Yakutat' => 'GMT-09:00 - Alaska, Gambier Islands (AKST)',
'Pacific/Gambier' => 'GMT-09:00 - Alaska, Gambier Islands (AKST)',
'America/Los_Angeles' => 'GMT-08:00 - Los Angeles, Vancouver, Tijuana (PST)',
'America/Santa_Isabel' => 'GMT-08:00 - Los Angeles, Vancouver, Tijuana (PST)',
'America/Tijuana' => 'GMT-08:00 - Los Angeles, Vancouver, Tijuana (PST)',
'America/Vancouver' => 'GMT-08:00 - Los Angeles, Vancouver, Tijuana (PST)',
'Pacific/Pitcairn' => 'GMT-08:00 - Los Angeles, Vancouver, Tijuana (PST)',
'America/Boise' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Cambridge_Bay' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Creston' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Dawson' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Dawson_Creek' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Denver' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Edmonton' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Fort_Nelson' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Hermosillo' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Inuvik' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Mazatlan' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Phoenix' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Whitehorse' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Yellowknife' => 'GMT-07:00 - Denver, Phoenix, Calgary (MST)',
'America/Bahia_Banderas' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Belize' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Chicago' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Chihuahua' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Costa_Rica' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/El_Salvador' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Guatemala' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Indiana/Knox' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Indiana/Tell_City' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Managua' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Matamoros' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Menominee' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Merida' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Mexico_City' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Monterrey' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/North_Dakota/Beulah' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/North_Dakota/Center' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/North_Dakota/New_Salem' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Ojinaga' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Rainy_River' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Rankin_Inlet' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Regina' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Resolute' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Swift_Current' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Tegucigalpa' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Winnipeg' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'Pacific/Galapagos' => 'GMT-06:00 - Chicago, Mexico City, Costa Rica, Galapagos (CST)',
'America/Bogota' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Cancun' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Cayman' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Coral_Harbour' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Detroit' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Eirunepe' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Grand_Turk' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Guayaquil' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Havana' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Indiana/Indianapolis' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Indiana/Marengo' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Indiana/Petersburg' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Indiana/Vevay' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Indiana/Vincennes' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Indiana/Winamac' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Iqaluit' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Jamaica' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Kentucky/Monticello' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Lima' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Louisville' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Montreal' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Nassau' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/New_York' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Nipigon' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Panama' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Pangnirtung' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Port-au-Prince' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Rio_Branco' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Thunder_Bay' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Toronto' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'Pacific/Easter' => 'GMT-05:00 - New York, Toronto, Lima, Bogota (EST)',
'America/Anguilla' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Antigua' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Aruba' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Barbados' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Blanc-Sablon' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Boa_Vista' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Campo_Grande' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Caracas' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Cuiaba' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Curacao' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Dominica' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Glace_Bay' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Goose_Bay' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Grenada' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Guadeloupe' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Guyana' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Halifax' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Kralendijk' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/La_Paz' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Lower_Princes' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Manaus' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Marigot' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Martinique' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Moncton' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Montserrat' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Port_of_Spain' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Porto_Velho' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Puerto_Rico' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Santo_Domingo' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/St_Barthelemy' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/St_Kitts' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/St_Lucia' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/St_Thomas' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/St_Vincent' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Thule' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/Tortola' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'Atlantic/Bermuda' => 'GMT-04:00 - Halifax, Santiago, Caracas, La Paz (AST)',
'America/St_Johns' => 'GMT-03:30 - St. John\'s (NST)',
'America/Araguaina' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Argentina/Buenos_Aires' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Argentina/La_Rioja' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Argentina/Rio_Gallegos' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Argentina/Salta' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Argentina/San_Juan' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Argentina/San_Luis' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Argentina/Tucuman' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Argentina/Ushuaia' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Asuncion' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Bahia' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Belem' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Catamarca' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Cayenne' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Cordoba' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Fortaleza' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Jujuy' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Maceio' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Mendoza' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Miquelon' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Montevideo' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Paramaribo' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Punta_Arenas' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Recife' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Santarem' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Santiago' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Sao_Paulo' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'Antarctica/Palmer' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'Antarctica/Rothera' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'Atlantic/Stanley' => 'GMT-03:00 - São Paulo, Buenos Aires, Montevideo (BRT)',
'America/Godthab' => 'GMT-02:00 - Fernando de Noronha, South Georgia (FNT)',
'America/Noronha' => 'GMT-02:00 - Fernando de Noronha, South Georgia (FNT)',
'America/Scoresbysund' => 'GMT-02:00 - Fernando de Noronha, South Georgia (FNT)',
'Atlantic/South_Georgia' => 'GMT-02:00 - Fernando de Noronha, South Georgia (FNT)',
'Atlantic/Azores' => 'GMT-01:00 - Cape Verde, Azores (CVT)',
'Atlantic/Cape_Verde' => 'GMT-01:00 - Cape Verde, Azores (CVT)',
'Africa/Abidjan' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Accra' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Bamako' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Banjul' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Bissau' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Casablanca' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Conakry' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Dakar' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/El_Aaiun' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Freetown' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Lome' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Monrovia' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Nouakchott' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Ouagadougou' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Sao_Tome' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'America/Danmarkshavn' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Antarctica/Troll' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Atlantic/Canary' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Atlantic/Faeroe' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Atlantic/Madeira' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Atlantic/Reykjavik' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Atlantic/St_Helena' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Europe/Dublin' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Europe/Guernsey' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Europe/Isle_of_Man' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Europe/Jersey' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Europe/Lisbon' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Europe/London' => 'GMT+00:00 - London, Dublin, Lisbon, Reykjavik, Accra (GMT)',
'Africa/Algiers' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Bangui' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Brazzaville' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Ceuta' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Douala' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Kinshasa' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Lagos' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Libreville' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Luanda' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Malabo' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Ndjamena' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Niamey' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Porto-Novo' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Africa/Tunis' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Arctic/Longyearbyen' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Amsterdam' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Andorra' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Belgrade' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Berlin' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Bratislava' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Brussels' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Budapest' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Busingen' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Copenhagen' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Gibraltar' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Ljubljana' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Luxembourg' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Madrid' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Malta' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Monaco' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Oslo' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Paris' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Podgorica' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Prague' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Rome' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/San_Marino' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Sarajevo' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Skopje' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Stockholm' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Tirane' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Vaduz' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Vatican' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Vienna' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Warsaw' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Zagreb' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)',
'Europe/Zurich' => 'GMT+01:00 - Paris, Berlin, Rome, Lagos, Kinshasa (CET)'
};
String query = 'SELECT Id, ' + sourceField + ', ' + targetField
    + ' FROM ' + sObjectName
    + ' WHERE ' + sourceField + ' != NULL'
    + ' AND ' + targetField + ' = NULL'
    + ' LIMIT ' + recordLimit;
List<SObject> records = Database.query(query);
List<SObject> toUpdate = new List<SObject>();
Integer matchCount = 0;
for (SObject rec : records) {
    String sfTz = (String) rec.get(sourceField);
    if (String.isNotBlank(sfTz) && tzMap.containsKey(sfTz)) {
        rec.put(targetField, tzMap.get(sfTz));
        toUpdate.add(rec);
        matchCount++;
    } 
}
if (!toUpdate.isEmpty()) {
    Database.SaveResult[] results = Database.update(toUpdate, false);
    Integer successCount = 0, failCount = 0;
    for (Database.SaveResult sr : results) {
        if (sr.isSuccess()) { successCount++; }
        else {
            failCount++;
            for (Database.Error e : sr.getErrors())
                System.debug('Update failed: ' + sr.getId() + ' | ' + e.getMessage());
        }
    }
    System.debug('=== PART 1 COMPLETE === Updated: ' + successCount + ' | Failed: ' + failCount);
} else {
    System.debug('=== PART 1: No matching records to update ===');
}

// ============================================================
// PART 2 
// Execute this salesforce developer console or workbench 
// ============================================================
String  sObjectName  = 'Account';                     // e.g. 'Account', 'Contact', 'Lead'
Integer recordLimit  = 5000;                          // Max limit 10000, Update as per org configuration 
String sourceField = 'Dialpad__Timezone__c';          // Old Text Field API
String targetField = 'Dialpad__Dialpad_Timezone__c'; // New Picklist Field API 
// ============================================================
// Creating old value to new value Map - 2nd set 
// ============================================================
Map<String, String> tzMap = new Map<String, String>{
'Africa/Blantyre' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Bujumbura' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Cairo' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Gaborone' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Harare' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Johannesburg' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Juba' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Khartoum' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Kigali' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Lubumbashi' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Lusaka' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Maputo' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Maseru' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Mbabane' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Tripoli' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Windhoek' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Asia/Beirut' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Asia/Famagusta' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Asia/Gaza' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Asia/Hebron' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Asia/Jerusalem' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Asia/Nicosia' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Athens' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Bucharest' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Chisinau' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Helsinki' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Kaliningrad' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Kyiv' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Mariehamn' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Riga' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Sofia' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Tallinn' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Uzhgorod' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Vilnius' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Europe/Zaporozhye' => 'GMT+02:00 - Cairo, Johannesburg, Helsinki, Kyiv, Jerusalem (EET)',
'Africa/Addis_Ababa' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Africa/Asmera' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Africa/Dar_es_Salaam' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Africa/Djibouti' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Africa/Kampala' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Africa/Mogadishu' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Africa/Nairobi' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Antarctica/Syowa' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Asia/Aden' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Asia/Amman' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Asia/Baghdad' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Asia/Bahrain' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Asia/Damascus' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Asia/Kuwait' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Asia/Qatar' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Asia/Riyadh' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Europe/Istanbul' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Europe/Kirov' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Europe/Minsk' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Europe/Moscow' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Europe/Simferopol' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Europe/Volgograd' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Indian/Antananarivo' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Indian/Comoro' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Indian/Mayotte' => 'GMT+03:00 - Moscow, Nairobi, Baghdad, Riyadh, Istanbul (MSK)',
'Asia/Tehran' => 'GMT+03:30 - Tehran (IRST)',
'Asia/Baku' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Asia/Dubai' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Asia/Muscat' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Asia/Tbilisi' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Asia/Yerevan' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Europe/Astrakhan' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Europe/Samara' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Europe/Saratov' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Europe/Ulyanovsk' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Indian/Mahe' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Indian/Mauritius' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Indian/Reunion' => 'GMT+04:00 - Dubai, Baku, Tbilisi, Mauritius (GST)',
'Asia/Kabul' => 'GMT+04:30 - Kabul (AFT)',
'Antarctica/Mawson' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Antarctica/Vostok' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Almaty' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Aqtau' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Aqtobe' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Ashgabat' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Atyrau' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Dushanbe' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Karachi' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Oral' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Qostanay' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Qyzylorda' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Samarkand' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Tashkent' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Yekaterinburg' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Indian/Kerguelen' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Indian/Maldives' => 'GMT+05:00 - Karachi, Islamabad, Tashkent, Yekaterinburg (PKT)',
'Asia/Colombo' => 'GMT+05:30 - New Delhi, Mumbai, Colombo (IST)',
'Asia/Kolkata' => 'GMT+05:30 - New Delhi, Mumbai, Colombo (IST)',
'Asia/Kathmandu' => 'GMT+05:45 - Kathmandu (NPT)',
'Asia/Bishkek' => 'GMT+06:00 - Dhaka, Almaty, Thimphu (BST)',
'Asia/Dhaka' => 'GMT+06:00 - Dhaka, Almaty, Thimphu (BST)',
'Asia/Omsk' => 'GMT+06:00 - Dhaka, Almaty, Thimphu (BST)',
'Asia/Thimphu' => 'GMT+06:00 - Dhaka, Almaty, Thimphu (BST)',
'Asia/Urumqi' => 'GMT+06:00 - Dhaka, Almaty, Thimphu (BST)',
'Indian/Chagos' => 'GMT+06:00 - Dhaka, Almaty, Thimphu (BST)',
'Asia/Rangoon' => 'GMT+06:30 - Yangon, Cocos Islands (MMT)',
'Indian/Cocos' => 'GMT+06:30 - Yangon, Cocos Islands (MMT)',
'Antarctica/Davis' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Bangkok' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Barnaul' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Ho_Chi_Minh' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Hovd' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Jakarta' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Krasnoyarsk' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Novokuznetsk' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Novosibirsk' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Phnom_Penh' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Pontianak' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Tomsk' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Asia/Vientiane' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Indian/Christmas' => 'GMT+07:00 - Bangkok, Jakarta, Hanoi, Ho Chi Minh City (ICT)',
'Antarctica/Casey' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Brunei' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Choibalsan' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Hong_Kong' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Irkutsk' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Kuala_Lumpur' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Kuching' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Macau' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Makassar' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Manila' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Shanghai' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Singapore' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Taipei' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Asia/Ulaanbaatar' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Australia/Perth' => 'GMT+08:00 - Beijing, Singapore, Hong Kong, Perth, Taipei (CST)',
'Australia/Eucla' => 'GMT+08:45 - Eucla (ACWST)',
'Asia/Chita' => 'GMT+09:00 - Tokyo, Seoul, Pyongyang (JST)',
'Asia/Dili' => 'GMT+09:00 - Tokyo, Seoul, Pyongyang (JST)',
'Asia/Jayapura' => 'GMT+09:00 - Tokyo, Seoul, Pyongyang (JST)',
'Asia/Khandyga' => 'GMT+09:00 - Tokyo, Seoul, Pyongyang (JST)',
'Asia/Pyongyang' => 'GMT+09:00 - Tokyo, Seoul, Pyongyang (JST)',
'Asia/Seoul' => 'GMT+09:00 - Tokyo, Seoul, Pyongyang (JST)',
'Asia/Tokyo' => 'GMT+09:00 - Tokyo, Seoul, Pyongyang (JST)',
'Asia/Yakutsk' => 'GMT+09:00 - Tokyo, Seoul, Pyongyang (JST)',
'Pacific/Palau' => 'GMT+09:00 - Tokyo, Seoul, Pyongyang (JST)',
'Australia/Darwin' => 'GMT+09:30 - Adelaide, Darwin (ACST)',
'Antarctica/DumontDUrville' => 'GMT+10:00 - Sydney, Brisbane, Guam, Port Moresby (AEST)',
'Asia/Ust-Nera' => 'GMT+10:00 - Sydney, Brisbane, Guam, Port Moresby (AEST)',
'Asia/Vladivostok' => 'GMT+10:00 - Sydney, Brisbane, Guam, Port Moresby (AEST)',
'Australia/Brisbane' => 'GMT+10:00 - Sydney, Brisbane, Guam, Port Moresby (AEST)',
'Australia/Lindeman' => 'GMT+10:00 - Sydney, Brisbane, Guam, Port Moresby (AEST)',
'Pacific/Guam' => 'GMT+10:00 - Sydney, Brisbane, Guam, Port Moresby (AEST)',
'Pacific/Port_Moresby' => 'GMT+10:00 - Sydney, Brisbane, Guam, Port Moresby (AEST)',
'Pacific/Saipan' => 'GMT+10:00 - Sydney, Brisbane, Guam, Port Moresby (AEST)',
'Pacific/Truk' => 'GMT+10:00 - Sydney, Brisbane, Guam, Port Moresby (AEST)',
'Australia/Adelaide' => 'GMT+10:30 - Lord Howe Island (LHST)',
'Australia/Broken_Hill' => 'GMT+10:30 - Lord Howe Island (LHST)',
'Antarctica/Macquarie' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Asia/Magadan' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Asia/Sakhalin' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Asia/Srednekolymsk' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Australia/Currie' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Australia/Hobart' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Australia/Lord_Howe' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Australia/Melbourne' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Australia/Sydney' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Pacific/Bougainville' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Pacific/Efate' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Pacific/Guadalcanal' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Pacific/Kosrae' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Pacific/Noumea' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Pacific/Ponape' => 'GMT+11:00 - Solomon Islands, Vanuatu, Magadan (SBT)',
'Asia/Anadyr' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Asia/Kamchatka' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Pacific/Fiji' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Pacific/Funafuti' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Pacific/Kwajalein' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Pacific/Majuro' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Pacific/Nauru' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Pacific/Norfolk' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Pacific/Tarawa' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Pacific/Wake' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Pacific/Wallis' => 'GMT+12:00 - Auckland, Fiji, Kamchatka (NZST)',
'Pacific/Chatham' => 'GMT+12:45 - Chatham Islands (CHAST)',
'Antarctica/McMurdo' => 'GMT+13:00 - Phoenix Islands, Tokelau, Tonga, Samoa (PHOT)',
'Pacific/Apia' => 'GMT+13:00 - Phoenix Islands, Tokelau, Tonga, Samoa (PHOT)',
'Pacific/Auckland' => 'GMT+13:00 - Phoenix Islands, Tokelau, Tonga, Samoa (PHOT)',
'Pacific/Enderbury' => 'GMT+13:00 - Phoenix Islands, Tokelau, Tonga, Samoa (PHOT)',
'Pacific/Fakaofo' => 'GMT+13:00 - Phoenix Islands, Tokelau, Tonga, Samoa (PHOT)',
'Pacific/Tongatapu' => 'GMT+13:00 - Phoenix Islands, Tokelau, Tonga, Samoa (PHOT)',
'Pacific/Kiritimati' => 'GMT+14:00 - Kiritimati/Line Islands (LINT)'
};
// ============================================================
// QUERY & UPDATE
// ============================================================
String query = 'SELECT Id, ' + sourceField + ', ' + targetField
    + ' FROM ' + sObjectName
    + ' WHERE ' + sourceField + ' != NULL'
    + ' AND ' + targetField + ' = NULL'
    + ' LIMIT ' + recordLimit;
List<SObject> records = Database.query(query);
List<SObject> toUpdate = new List<SObject>();
Integer matchCount = 0;
for (SObject rec : records) {
    String sfTz = (String) rec.get(sourceField);
    if (String.isNotBlank(sfTz) && tzMap.containsKey(sfTz)) {
        rec.put(targetField, tzMap.get(sfTz));
        toUpdate.add(rec);
        matchCount++;
    } 
}
if (!toUpdate.isEmpty()) {
    Database.SaveResult[] results = Database.update(toUpdate, false);
    Integer successCount = 0, failCount = 0;
    for (Database.SaveResult sr : results) {
        if (sr.isSuccess()) { successCount++; }
        else {
            failCount++;
            for (Database.Error e : sr.getErrors())
                System.debug('Update failed: ' + sr.getId() + ' | ' + e.getMessage());
        }
    }
    System.debug('=== PART 2 COMPLETE === Updated: ' + successCount + ' | Failed: ' + failCount);
} else {
    System.debug('=== PART 2: NO RECORDS TO UPDATE ===');
}