1 00:00:00,000 --> 00:00:02,220 Welcome to another episode of Microsoft Knowledge Nuggets. 2 00:00:02,220 --> 00:00:03,940 I'm your host, Mirko Peters. 3 00:00:03,940 --> 00:00:05,140 So here's the scenario. 4 00:00:05,140 --> 00:00:06,700 You're working in Business Central 5 00:00:06,700 --> 00:00:08,400 and you need one small change. 6 00:00:08,400 --> 00:00:10,420 Maybe an extra field on a customer record, 7 00:00:10,420 --> 00:00:11,880 a different approval step, 8 00:00:11,880 --> 00:00:14,440 or a rule that checks an order before someone posts it. 9 00:00:14,440 --> 00:00:16,860 Then someone brings up AL, extensions, 10 00:00:16,860 --> 00:00:18,740 tables, pages, and code units, 11 00:00:18,740 --> 00:00:21,880 and suddenly that small request sounds like a whole new language. 12 00:00:21,880 --> 00:00:24,500 It's a language, sure, but it doesn't have to feel mysterious. 13 00:00:24,500 --> 00:00:26,620 Think of Business Central as an office building. 14 00:00:26,620 --> 00:00:30,020 AL gives developers the instructions to add a room, a form, 15 00:00:30,020 --> 00:00:33,120 or a new rule without knocking holes through the building itself. 16 00:00:33,120 --> 00:00:34,840 That's the knowledge nugget for today. 17 00:00:34,840 --> 00:00:35,960 By the end of this episode, 18 00:00:35,960 --> 00:00:39,280 you'll know what AL development means, why extensions exist, 19 00:00:39,280 --> 00:00:42,120 and how custom work fits into Business Central. 20 00:00:42,120 --> 00:00:43,920 Why Businesses Customize Business Central? 21 00:00:43,920 --> 00:00:46,520 Business Central already handles a lot of daily worker finance, 22 00:00:46,520 --> 00:00:48,560 customers, sales orders, stock invoices, 23 00:00:48,560 --> 00:00:51,080 all in one connected system instead of a pile of spreadsheets 24 00:00:51,080 --> 00:00:52,200 and separate tools. 25 00:00:52,200 --> 00:00:55,360 For many companies, that standard setup covers most of the job. 26 00:00:55,360 --> 00:00:58,400 But here's the thing, no two companies work the same way. 27 00:00:58,400 --> 00:01:00,480 Take a food distributor needing batch details, 28 00:01:00,480 --> 00:01:02,120 another company never uses, 29 00:01:02,120 --> 00:01:04,520 a service business requiring a special approval process 30 00:01:04,520 --> 00:01:08,520 before invoicing, a retailer wanting reward levels for discounts, 31 00:01:08,520 --> 00:01:10,960 and someone else needing a form with their own wording, 32 00:01:10,960 --> 00:01:12,800 fields, and internal rules. 33 00:01:12,800 --> 00:01:16,280 The business won't change its ways for one missing field, 34 00:01:16,280 --> 00:01:18,040 and you don't want every small request 35 00:01:18,040 --> 00:01:20,680 to turn into a risky change to the whole system either. 36 00:01:20,680 --> 00:01:22,120 That used to be a bigger problem. 37 00:01:22,120 --> 00:01:23,320 In older systems, 38 00:01:23,320 --> 00:01:26,280 developers opened the original code and edited it directly, 39 00:01:26,280 --> 00:01:28,400 and it worked until the next update arrived. 40 00:01:28,400 --> 00:01:31,320 Then the company had Microsoft's new version on one side, 41 00:01:31,320 --> 00:01:33,000 its own changes on the other, 42 00:01:33,000 --> 00:01:34,840 and someone had to reconcile everything 43 00:01:34,840 --> 00:01:36,840 before the update could move forward. 44 00:01:36,840 --> 00:01:39,200 Picture an office where every tenant runs new cables 45 00:01:39,200 --> 00:01:41,640 through the walls without a plan. 46 00:01:41,640 --> 00:01:44,040 It works for a while, but when the building needs repairs, 47 00:01:44,040 --> 00:01:46,760 nobody knows which cable belongs to whom. 48 00:01:46,760 --> 00:01:48,480 Business Central takes a different route. 49 00:01:48,480 --> 00:01:50,440 Instead of rewriting the standard application, 50 00:01:50,440 --> 00:01:53,040 developers build a separate add-on that connects to it, 51 00:01:53,040 --> 00:01:54,480 keeping the standard part in place 52 00:01:54,480 --> 00:01:56,600 while the company's own changes sit beside it 53 00:01:56,600 --> 00:01:59,200 and work through supported points in the system. 54 00:01:59,200 --> 00:02:01,000 That separation matters when updates arrive 55 00:02:01,000 --> 00:02:03,360 because Microsoft updates its part of the building 56 00:02:03,360 --> 00:02:05,640 while the custom works stays in its own space. 57 00:02:05,640 --> 00:02:08,840 There are still tests and fixes, software changes after all, 58 00:02:08,840 --> 00:02:11,520 but the developer isn't expected to copy and rework 59 00:02:11,520 --> 00:02:14,360 every change inside Microsoft's original code. 60 00:02:14,360 --> 00:02:16,000 So what does a business actually customize? 61 00:02:16,000 --> 00:02:17,600 The customizations add data. 62 00:02:17,600 --> 00:02:20,200 The standard system doesn't store like delivery instructions 63 00:02:20,200 --> 00:02:22,560 and internal risk score, a membership level, 64 00:02:22,560 --> 00:02:24,160 or a link to an outside system, 65 00:02:24,160 --> 00:02:25,840 and they add screens that guide staff 66 00:02:25,840 --> 00:02:27,600 through a task in the right order. 67 00:02:27,600 --> 00:02:29,600 They also enforce rules like stopping an order 68 00:02:29,600 --> 00:02:31,480 when a required document is missing. 69 00:02:31,480 --> 00:02:34,120 Custom work also helps people avoid manual steps. 70 00:02:34,120 --> 00:02:36,680 Imagine staff copying customer data from business central 71 00:02:36,680 --> 00:02:38,160 into another tool every Friday, 72 00:02:38,160 --> 00:02:39,600 checking conditions by hand, 73 00:02:39,600 --> 00:02:41,440 then sending a report to a manager. 74 00:02:41,440 --> 00:02:44,320 A well-built change keeps that information in business central, 75 00:02:44,320 --> 00:02:45,840 applies the rule consistently, 76 00:02:45,840 --> 00:02:48,760 and gives staff a button or page that fits their daily work. 77 00:02:48,760 --> 00:02:49,760 Let's clear up a myth. 78 00:02:49,760 --> 00:02:51,680 You don't want to customize everything. 79 00:02:51,680 --> 00:02:54,680 Standard business central already has many processes built in, 80 00:02:54,680 --> 00:02:56,200 changing something just because it looks different 81 00:02:56,200 --> 00:02:58,520 from an old system creates extra work later, 82 00:02:58,520 --> 00:03:01,280 so good custom work starts with a clear business reason. 83 00:03:01,280 --> 00:03:03,080 What problem are people facing? 84 00:03:03,080 --> 00:03:04,360 What should happen instead? 85 00:03:04,360 --> 00:03:06,960 And can the standard product already do it? 86 00:03:06,960 --> 00:03:09,000 When the standard product doesn't meet that need, 87 00:03:09,000 --> 00:03:10,600 AL enters the picture. 88 00:03:10,600 --> 00:03:12,400 AL focuses on business central itself, 89 00:03:12,400 --> 00:03:15,120 reading, adding, and changing records at the database level 90 00:03:15,120 --> 00:03:17,160 while controlling what happens on pages, reports, 91 00:03:17,160 --> 00:03:18,800 and other parts of the application, 92 00:03:18,800 --> 00:03:21,240 and it calculates values, moves data, 93 00:03:21,240 --> 00:03:24,200 and shows messages when rules fail throughout processes. 94 00:03:24,200 --> 00:03:25,760 That's a lot of work for one language, 95 00:03:25,760 --> 00:03:28,440 but AL isn't a general tool for every type of software, 96 00:03:28,440 --> 00:03:31,120 and you wouldn't choose it to build a public shopping website, 97 00:03:31,120 --> 00:03:34,480 a mobile game, or a standalone desktop app. 98 00:03:34,480 --> 00:03:36,560 AL exists for one focused job, 99 00:03:36,560 --> 00:03:38,880 shaping the data and behavior inside business central, 100 00:03:38,880 --> 00:03:40,920 so the system matches how a company operates, 101 00:03:40,920 --> 00:03:43,080 and that's exactly what we'll look at next. 102 00:03:43,080 --> 00:03:45,600 AL in extensions, the safe add-on model. 103 00:03:45,600 --> 00:03:48,960 AL stands for application language. 104 00:03:48,960 --> 00:03:51,800 It's Microsoft's programming language for business central, 105 00:03:51,800 --> 00:03:53,680 and it gives developers a structured way 106 00:03:53,680 --> 00:03:55,200 to create new business functions 107 00:03:55,200 --> 00:03:57,960 or change how existing parts of the system behave. 108 00:03:57,960 --> 00:04:00,800 But the word extension is just as important as AL. 109 00:04:00,800 --> 00:04:03,400 An extension is a separate app that business central can install. 110 00:04:03,400 --> 00:04:05,200 It holds the company's custom work 111 00:04:05,200 --> 00:04:08,480 while the standard business central application stays untouched. 112 00:04:08,480 --> 00:04:10,200 Think of it less like rewriting a handbook 113 00:04:10,200 --> 00:04:12,240 and more like adding approved pages to it. 114 00:04:12,240 --> 00:04:15,240 O pages that follow the original rules without erasing them. 115 00:04:15,240 --> 00:04:16,600 That might sound like a technical detail, 116 00:04:16,600 --> 00:04:19,040 but it changes how custom work lives over time. 117 00:04:19,040 --> 00:04:22,000 Imagine a company needs a new office room for a special team. 118 00:04:22,000 --> 00:04:23,560 The old approach meant breaking through a wall 119 00:04:23,560 --> 00:04:26,000 in the main building and changing the structure itself. 120 00:04:26,000 --> 00:04:27,640 It might solve the need today, 121 00:04:27,640 --> 00:04:29,440 but future repairs become a nightmare 122 00:04:29,440 --> 00:04:32,680 because the original building no longer matches its blueprints 123 00:04:32,680 --> 00:04:34,280 and extension works differently. 124 00:04:34,280 --> 00:04:36,320 The building already has doors, power points, 125 00:04:36,320 --> 00:04:38,000 and rules for adding space. 126 00:04:38,000 --> 00:04:40,400 You build the new room through those approved connections, 127 00:04:40,400 --> 00:04:41,560 the room belongs to the company, 128 00:04:41,560 --> 00:04:43,360 but the main building can still receive maintenance 129 00:04:43,360 --> 00:04:45,120 without tearing apart every custom wall. 130 00:04:45,120 --> 00:04:47,560 That's exactly how business central extensions work. 131 00:04:47,560 --> 00:04:50,840 The base application contains the standard work Microsoft supplies. 132 00:04:50,840 --> 00:04:52,520 An extension can add its own fields, 133 00:04:52,520 --> 00:04:55,800 screens, buttons, rules, reports, and even links to other systems. 134 00:04:55,800 --> 00:04:58,400 It can react when certain business actions happen, 135 00:04:58,400 --> 00:05:00,280 but it does this through supported ways 136 00:05:00,280 --> 00:05:02,000 of connecting to the standard application. 137 00:05:02,000 --> 00:05:03,360 So boundaries are built in. 138 00:05:03,360 --> 00:05:04,320 That's a good thing. 139 00:05:04,320 --> 00:05:06,120 Without boundaries, a small custom request 140 00:05:06,120 --> 00:05:08,280 can reach deep into areas it shouldn't touch. 141 00:05:08,280 --> 00:05:09,880 With extensions, the developer works 142 00:05:09,880 --> 00:05:12,840 with clear object types and defined connection points. 143 00:05:12,840 --> 00:05:14,920 That makes the code easier to understand 144 00:05:14,920 --> 00:05:16,800 when someone else needs to read it later. 145 00:05:16,800 --> 00:05:18,600 This approach also fits the cloud version 146 00:05:18,600 --> 00:05:19,960 of business central perfectly. 147 00:05:19,960 --> 00:05:22,280 Microsoft updates the service regularly. 148 00:05:22,280 --> 00:05:25,160 A company still needs to test its extension after changes, 149 00:05:25,160 --> 00:05:27,120 especially if it depends on parts of the product 150 00:05:27,120 --> 00:05:28,040 that have changed. 151 00:05:28,040 --> 00:05:30,320 Software never removes the need for care. 152 00:05:30,320 --> 00:05:32,640 But keeping custom code separate lowers the chance 153 00:05:32,640 --> 00:05:36,440 that every update turns into a major rebuild of old modifications. 154 00:05:36,440 --> 00:05:38,560 You may hear people mention CAL when they talk 155 00:05:38,560 --> 00:05:40,480 about older dynamics nav systems. 156 00:05:40,480 --> 00:05:43,200 CAL came from an earlier development model 157 00:05:43,200 --> 00:05:45,800 where developers often change the original application objects 158 00:05:45,800 --> 00:05:46,600 directly. 159 00:05:46,600 --> 00:05:49,320 Many companies ran successful systems that way for years. 160 00:05:49,320 --> 00:05:52,720 But it tied custom work much more closely to the standard code 161 00:05:52,720 --> 00:05:55,560 and updates required a lot of comparison and repair work. 162 00:05:55,560 --> 00:05:58,280 AL moved business central toward app-based development. 163 00:05:58,280 --> 00:06:00,880 That doesn't mean every extension is large or complicated. 164 00:06:00,880 --> 00:06:03,480 One extension might only add a feel to a customer record 165 00:06:03,480 --> 00:06:05,200 and show it on a familiar screen. 166 00:06:05,200 --> 00:06:07,080 Another might contain a full solution 167 00:06:07,080 --> 00:06:08,680 for a particular business type 168 00:06:08,680 --> 00:06:12,000 with its own records, processes, pages, and reports. 169 00:06:12,000 --> 00:06:14,080 Both follow the same basic idea. 170 00:06:14,080 --> 00:06:16,320 The custom app lives beside business central instead 171 00:06:16,320 --> 00:06:17,760 of hiding a rewrite of it. 172 00:06:17,760 --> 00:06:20,040 You can also install more than one extension. 173 00:06:20,040 --> 00:06:22,480 A company might use an extension from a software partner, 174 00:06:22,480 --> 00:06:24,200 for payroll, another for shipping, 175 00:06:24,200 --> 00:06:26,120 and a small internal extension for rules 176 00:06:26,120 --> 00:06:28,000 that only matter to that company. 177 00:06:28,000 --> 00:06:30,560 Business central brings them together in the same working 178 00:06:30,560 --> 00:06:32,840 system as long as they follow the platform's rules 179 00:06:32,840 --> 00:06:33,920 and don't conflict. 180 00:06:33,920 --> 00:06:35,720 So AL isn't just a way to write code. 181 00:06:35,720 --> 00:06:38,560 It's the language developers use to create these add-on apps. 182 00:06:38,560 --> 00:06:40,120 And extensions are the container that 183 00:06:40,120 --> 00:06:42,520 carries those changes into business central. 184 00:06:42,520 --> 00:06:44,360 That model lets the company tailor the system 185 00:06:44,360 --> 00:06:46,240 while keeping the standard product recognizable 186 00:06:46,240 --> 00:06:47,520 and easier to maintain. 187 00:06:47,520 --> 00:06:49,040 Now let's open one of these extensions 188 00:06:49,040 --> 00:06:51,600 and look at the building blocks inside it. 189 00:06:51,600 --> 00:06:54,360 The main AL building blocks inside an AL extension 190 00:06:54,360 --> 00:06:56,080 developers work with objects. 191 00:06:56,080 --> 00:06:57,720 An object is one named piece of the app 192 00:06:57,720 --> 00:06:59,760 with a clear job, like storing information, 193 00:06:59,760 --> 00:07:02,960 showing a screen, running a rule, or producing a document. 194 00:07:02,960 --> 00:07:04,440 Once you see those jobs separately, 195 00:07:04,440 --> 00:07:07,000 AL starts to feel much less like a wall of code. 196 00:07:07,000 --> 00:07:09,680 Let's start with the place where business information lives. 197 00:07:09,680 --> 00:07:11,640 Table store data in business central. 198 00:07:11,640 --> 00:07:13,600 Think of a table as a digital filing cabinet 199 00:07:13,600 --> 00:07:14,880 for one type of record. 200 00:07:14,880 --> 00:07:17,560 One cabinet might hold customers, another holds items, 201 00:07:17,560 --> 00:07:19,160 and another holds sales orders. 202 00:07:19,160 --> 00:07:21,560 Each record is one file inside that cabinet. 203 00:07:21,560 --> 00:07:24,400 A customer table contains one record for each customer. 204 00:07:24,400 --> 00:07:27,360 An item table contains one record for each product. 205 00:07:27,360 --> 00:07:28,800 If your company needs information 206 00:07:28,800 --> 00:07:30,760 that standard business central doesn't store, 207 00:07:30,760 --> 00:07:33,200 an extension can create its own table AU, 208 00:07:33,200 --> 00:07:35,680 maybe for reward levels, equipment inspections, 209 00:07:35,680 --> 00:07:37,280 or project approvals. 210 00:07:37,280 --> 00:07:39,800 These fields are the labeled spaces inside each record. 211 00:07:39,800 --> 00:07:41,640 A customer record can include a name, 212 00:07:41,640 --> 00:07:43,760 an address, a payment term, and a phone number 213 00:07:43,760 --> 00:07:45,760 because the customer table contains fields 214 00:07:45,760 --> 00:07:46,960 for those details. 215 00:07:46,960 --> 00:07:50,360 Fields can hold text, dates, amounts, yes or no answers, 216 00:07:50,360 --> 00:07:52,080 or a choice from a fixed list. 217 00:07:52,080 --> 00:07:53,800 A field can also point to another record. 218 00:07:53,800 --> 00:07:56,520 For example, a customer could contain a reward ID field. 219 00:07:56,520 --> 00:07:58,360 Instead of typing any random text, 220 00:07:58,360 --> 00:08:01,320 staff select a reward level from a separate reward table. 221 00:08:01,320 --> 00:08:02,840 That link keeps the data clean 222 00:08:02,840 --> 00:08:05,000 because everyone chooses from the same known list. 223 00:08:05,000 --> 00:08:06,320 So tables hold the facts. 224 00:08:06,320 --> 00:08:08,480 But how do people see and work with those facts? 225 00:08:08,480 --> 00:08:09,320 Pages. 226 00:08:09,320 --> 00:08:11,200 A page is the screen you open in business central. 227 00:08:11,200 --> 00:08:12,760 The customer card is a page. 228 00:08:12,760 --> 00:08:14,560 A list of sales orders is a page. 229 00:08:14,560 --> 00:08:17,240 A page controls what users can view, enter, search for, 230 00:08:17,240 --> 00:08:18,080 and act on. 231 00:08:18,080 --> 00:08:19,920 Different pages fit different jobs. 232 00:08:19,920 --> 00:08:21,960 A cart page focuses on one record at a time 233 00:08:21,960 --> 00:08:23,760 like one customer or one item. 234 00:08:23,760 --> 00:08:25,640 A list page shows many records in rows, 235 00:08:25,640 --> 00:08:28,160 which works well when you need to scan, filter, 236 00:08:28,160 --> 00:08:29,640 or find something quickly. 237 00:08:29,640 --> 00:08:31,360 A worksheet page supports work 238 00:08:31,360 --> 00:08:33,360 where people enter or process several lines 239 00:08:33,360 --> 00:08:34,640 of information together. 240 00:08:34,640 --> 00:08:36,200 The table stores the information. 241 00:08:36,200 --> 00:08:38,240 The page puts it in front of the user. 242 00:08:38,240 --> 00:08:40,680 That separation is helpful because you can change the screen 243 00:08:40,680 --> 00:08:42,440 without changing where the data lives, 244 00:08:42,440 --> 00:08:45,240 or reuse the same table on more than one page 245 00:08:45,240 --> 00:08:47,000 when different teams need different views 246 00:08:47,000 --> 00:08:48,160 of the same records. 247 00:08:48,160 --> 00:08:49,600 Now, what if the data already belongs 248 00:08:49,600 --> 00:08:51,400 on a standard business central record? 249 00:08:51,400 --> 00:08:53,560 You usually don't create a replacement customer table 250 00:08:53,560 --> 00:08:55,120 just because you need one extra field. 251 00:08:55,120 --> 00:08:56,480 You use a table extension. 252 00:08:56,480 --> 00:08:58,080 A table extension adds your field 253 00:08:58,080 --> 00:08:59,800 to the existing customer table. 254 00:08:59,800 --> 00:09:02,200 The standard customer record stays where it belongs. 255 00:09:02,200 --> 00:09:04,600 While your extension adds the company's specific detail 256 00:09:04,600 --> 00:09:06,120 beside the standard fields. 257 00:09:06,120 --> 00:09:07,960 That might be a reward ID, a delivery note, 258 00:09:07,960 --> 00:09:09,920 an account manager, or a field that connects 259 00:09:09,920 --> 00:09:11,200 to another part of the business. 260 00:09:11,200 --> 00:09:12,560 But adding the field to the table 261 00:09:12,560 --> 00:09:14,760 doesn't automatically put it on the screen. 262 00:09:14,760 --> 00:09:16,120 For that, you use a page extension. 263 00:09:16,120 --> 00:09:18,480 A page extension adds a field, group, or action 264 00:09:18,480 --> 00:09:19,800 to an existing page. 265 00:09:19,800 --> 00:09:21,920 If the business needs staff to choose a reward level 266 00:09:21,920 --> 00:09:23,960 while viewing a customer, the page extension 267 00:09:23,960 --> 00:09:26,320 can place the reward ID field on the customer card, 268 00:09:26,320 --> 00:09:27,840 right where staff already work. 269 00:09:27,840 --> 00:09:29,640 That keeps the experience familiar. 270 00:09:29,640 --> 00:09:31,920 Instead of sending users to a separate custom screen 271 00:09:31,920 --> 00:09:34,160 for a simple detail, the extension adds the detail 272 00:09:34,160 --> 00:09:35,680 to the page they already know. 273 00:09:35,680 --> 00:09:38,840 A page extension can also add an action on us, a button, 274 00:09:38,840 --> 00:09:40,560 or a menu command that starts a task. 275 00:09:40,560 --> 00:09:43,400 For example, a customer card could include a reward action 276 00:09:43,400 --> 00:09:45,040 that opens the reward list. 277 00:09:45,040 --> 00:09:47,720 Behind the screen, you need a home for the business rules. 278 00:09:47,720 --> 00:09:49,200 That home is often a code unit. 279 00:09:49,200 --> 00:09:51,280 A code unit contains AL procedures, which 280 00:09:51,280 --> 00:09:53,440 are named pieces of code that do a particular job. 281 00:09:53,440 --> 00:09:55,120 Think of it as the back office team that 282 00:09:55,120 --> 00:09:58,120 handles a task when a page report or another process 283 00:09:58,120 --> 00:09:59,040 asks for help. 284 00:09:59,040 --> 00:10:01,480 Suppose the reward level decides which discount 285 00:10:01,480 --> 00:10:02,840 applies to a customer. 286 00:10:02,840 --> 00:10:05,040 The discount calculation belongs in a code unit, 287 00:10:05,040 --> 00:10:07,280 not in the customer card page itself. 288 00:10:07,280 --> 00:10:10,160 Then a sales process, a report, or a future page 289 00:10:10,160 --> 00:10:13,440 can use the same rule without copying it into several places. 290 00:10:13,440 --> 00:10:15,360 One rule, one place to maintain it. 291 00:10:15,360 --> 00:10:17,400 Business Central also includes other object types 292 00:10:17,400 --> 00:10:18,400 for different jobs. 293 00:10:18,400 --> 00:10:21,160 Reports collect data and present it in a document or layout 294 00:10:21,160 --> 00:10:23,280 like an invoice or a sales report. 295 00:10:23,280 --> 00:10:25,360 Queries ask focused questions across data, 296 00:10:25,360 --> 00:10:28,280 a U, which customers order the certain item during a period, 297 00:10:28,280 --> 00:10:31,400 for example, XML ports help bring data in or send it out 298 00:10:31,400 --> 00:10:33,800 in a structured format, often when another system needs 299 00:10:33,800 --> 00:10:35,560 to exchange information with Business Central, 300 00:10:35,560 --> 00:10:37,160 put those pieces together and you can picture 301 00:10:37,160 --> 00:10:39,280 a small customer rewards extension. 302 00:10:39,280 --> 00:10:42,280 A reward table stores each level and its discount percentage. 303 00:10:42,280 --> 00:10:44,720 Reward pages let staff manage those levels. 304 00:10:44,720 --> 00:10:47,760 A customer table extension adds a reward ID to each customer 305 00:10:47,760 --> 00:10:50,120 while a customer card page extension displays it. 306 00:10:50,120 --> 00:10:51,920 A page action opens the reward list 307 00:10:51,920 --> 00:10:54,400 and the code unit calculates the discount rule. 308 00:10:54,400 --> 00:10:56,720 Each object handles one part of the job. 309 00:10:56,720 --> 00:10:59,920 That makes the extension easier to read, test, and change 310 00:10:59,920 --> 00:11:02,040 when the business rule changes six months later. 311 00:11:02,040 --> 00:11:05,000 But a business rule often needs to run at exactly the right moment 312 00:11:05,000 --> 00:11:06,800 such as when someone posts an order. 313 00:11:06,800 --> 00:11:08,480 That's where triggers and events come in. 314 00:11:08,480 --> 00:11:10,400 Events triggers and business rules. 315 00:11:10,400 --> 00:11:12,120 Welcome back to another knowledge nugget. 316 00:11:12,120 --> 00:11:14,720 I'm Mirko Peters and today we're breaking down events, 317 00:11:14,720 --> 00:11:16,960 triggers, and business rules in Business Central 318 00:11:16,960 --> 00:11:19,080 so you've added a customer reward field. 319 00:11:19,080 --> 00:11:20,560 Good, here's the real question. 320 00:11:20,560 --> 00:11:22,680 When should Business Central actually use that field? 321 00:11:22,680 --> 00:11:24,600 Imagine you're about to post a sales order. 322 00:11:24,600 --> 00:11:26,640 Before the system creates the final entries, 323 00:11:26,640 --> 00:11:28,000 you want one extra check. 324 00:11:28,000 --> 00:11:30,000 Maybe the customer needs an approved reward level 325 00:11:30,000 --> 00:11:31,520 before a discount kicks in. 326 00:11:31,520 --> 00:11:34,280 Or maybe a required delivery document must exist 327 00:11:34,280 --> 00:11:36,160 before the order can move forward. 328 00:11:36,160 --> 00:11:37,720 You want that check at the right moment. 329 00:11:37,720 --> 00:11:40,280 But you don't want to copy the entire sales posting process 330 00:11:40,280 --> 00:11:42,480 into your own extension just to add one rule. 331 00:11:42,480 --> 00:11:44,840 That process already handles a lot behind the scenes. 332 00:11:44,840 --> 00:11:47,120 If you copy it, your extension is now stuck 333 00:11:47,120 --> 00:11:49,600 maintaining all those future changes, not ideal. 334 00:11:49,600 --> 00:11:52,160 So AL gives developers a few ways to run code. 335 00:11:52,160 --> 00:11:54,680 Which one you pick depends on what needs to happen. 336 00:11:54,680 --> 00:11:55,840 First up, triggers. 337 00:11:55,840 --> 00:11:58,240 A trigger is a name spot inside an AL object 338 00:11:58,240 --> 00:11:59,400 where code can run. 339 00:11:59,400 --> 00:12:01,480 When someone changes a value on a table field, 340 00:12:01,480 --> 00:12:02,880 the trigger fires code. 341 00:12:02,880 --> 00:12:05,360 When a page opens or closes the trigger fires code, 342 00:12:05,360 --> 00:12:08,360 reports, queries, XML ports, tables, extensions, AL, 343 00:12:08,360 --> 00:12:10,760 they all have these spots where a developer can add rules. 344 00:12:10,760 --> 00:12:12,600 Take the reward ID field on a customer. 345 00:12:12,600 --> 00:12:15,840 When a user picks a reward level, a validation trigger can run. 346 00:12:15,840 --> 00:12:17,680 The code checks is the customer blocked. 347 00:12:17,680 --> 00:12:19,320 Does the reward level exist? 348 00:12:19,320 --> 00:12:20,880 Does another field need an update? 349 00:12:20,880 --> 00:12:23,160 The check happens right when the value changes. 350 00:12:23,160 --> 00:12:25,160 Not later when someone discovers a mistake. 351 00:12:25,160 --> 00:12:28,160 Triggers work well when the rule belongs closely to that object. 352 00:12:28,160 --> 00:12:30,160 But Business Central also uses events. 353 00:12:30,160 --> 00:12:31,240 An event is like a notice. 354 00:12:31,240 --> 00:12:34,760 One part of the application sends it when something happens. 355 00:12:34,760 --> 00:12:37,760 It might announce that a record is about to be inserted 356 00:12:37,760 --> 00:12:39,760 or that a document is about to post. 357 00:12:39,760 --> 00:12:41,720 Or that a process has finished, your extension 358 00:12:41,720 --> 00:12:42,960 can listen for that notice. 359 00:12:42,960 --> 00:12:45,680 The code that listens is called an event subscriber. 360 00:12:45,680 --> 00:12:47,320 It waits for a specific named event. 361 00:12:47,320 --> 00:12:49,240 When Business Central raises that event, 362 00:12:49,240 --> 00:12:51,040 the subscriber runs its own procedure. 363 00:12:51,040 --> 00:12:52,880 The standard process stays in charge. 364 00:12:52,880 --> 00:12:55,520 For example, when Business Central begins posting a sales order, 365 00:12:55,520 --> 00:12:57,680 it raises an event before continuing. 366 00:12:57,680 --> 00:12:59,640 Your reward's extension receives that notice. 367 00:12:59,640 --> 00:13:02,000 It checks the customer's reward ID and discount rule. 368 00:13:02,000 --> 00:13:04,200 Then it either allows the process to continue 369 00:13:04,200 --> 00:13:06,000 or stops it with a clear message. 370 00:13:06,000 --> 00:13:09,520 The standard posting process still belongs to Business Central. 371 00:13:09,520 --> 00:13:11,880 Your extension just adds its company-specific rule 372 00:13:11,880 --> 00:13:13,200 at that connection point. 373 00:13:13,200 --> 00:13:16,720 You'll often hear event names like on before or on after. 374 00:13:16,720 --> 00:13:19,600 On before means your code runs before an action finishes. 375 00:13:19,600 --> 00:13:21,800 That's perfect for a check that can prevent the next step, 376 00:13:21,800 --> 00:13:25,480 oh, like stopping a sales order if a condition fails. 377 00:13:25,480 --> 00:13:27,360 After means the action already happened, 378 00:13:27,360 --> 00:13:30,240 you can react, create a related record, update a note, 379 00:13:30,240 --> 00:13:31,800 or start another piece of work. 380 00:13:31,800 --> 00:13:34,080 The names tell you the timing and timing matters. 381 00:13:34,080 --> 00:13:36,560 A rule that runs after posting can't prevent it. 382 00:13:36,560 --> 00:13:39,560 A rule that runs too early may not have the data it needs. 383 00:13:39,560 --> 00:13:41,080 So developers pick the event based 384 00:13:41,080 --> 00:13:43,000 on what the business rule must do and when. 385 00:13:43,000 --> 00:13:44,720 Code can also start from an action. 386 00:13:44,720 --> 00:13:47,440 A user clicks a button like check reward status 387 00:13:47,440 --> 00:13:49,640 and that action calls a procedure. 388 00:13:49,640 --> 00:13:52,680 Code can also run when one object calls another through a variable 389 00:13:52,680 --> 00:13:54,520 that sounds technical, but it's simple. 390 00:13:54,520 --> 00:13:57,520 One part of the extension asks another to perform a job. 391 00:13:57,520 --> 00:13:58,720 Variables help with that. 392 00:13:58,720 --> 00:14:02,440 A variable is a named place that holds a value while code runs. 393 00:14:02,440 --> 00:14:04,160 It could be a number, text, a date, 394 00:14:04,160 --> 00:14:06,720 or even a business central record like the current customer. 395 00:14:06,720 --> 00:14:08,880 In AL, you declare them with var. 396 00:14:08,880 --> 00:14:11,480 For example, a rewards procedure might use a variable 397 00:14:11,480 --> 00:14:14,120 called customer to hold the current customer record. 398 00:14:14,120 --> 00:14:16,400 Another variable called discount percent holds 399 00:14:16,400 --> 00:14:17,600 the discounted fines. 400 00:14:17,600 --> 00:14:18,800 These aren't permanent records. 401 00:14:18,800 --> 00:14:20,880 They're just working values for that piece of code. 402 00:14:20,880 --> 00:14:22,600 Here's the thing about where code lives. 403 00:14:22,600 --> 00:14:24,480 If a rule might be used from more than one place, 404 00:14:24,480 --> 00:14:25,640 put it in a code unit. 405 00:14:25,640 --> 00:14:28,760 That way, the customer card, a sales process, and a report 406 00:14:28,760 --> 00:14:30,760 can all call the same discount procedure 407 00:14:30,760 --> 00:14:33,480 instead of each having its own version. 408 00:14:33,480 --> 00:14:35,040 That avoids a familiar problem. 409 00:14:35,040 --> 00:14:38,600 One screen applies a 10% discount, another applies 5%, 410 00:14:38,600 --> 00:14:40,680 and nobody knows which rule to trust. 411 00:14:40,680 --> 00:14:43,120 Keeping shared business rules in one code unit 412 00:14:43,120 --> 00:14:45,520 gives the extension one source for that decision. 413 00:14:45,520 --> 00:14:48,200 So triggers handle rules close to an object, 414 00:14:48,200 --> 00:14:51,520 events let an extension react to business central's own processes. 415 00:14:51,520 --> 00:14:53,680 Code units keep shared logic together. 416 00:14:53,680 --> 00:14:55,840 Once those pieces connect, the next question is, 417 00:14:55,840 --> 00:14:59,200 where do developers write, test, and inspect all this AL code? 418 00:14:59,200 --> 00:15:00,800 Or where AL development happens, 419 00:15:00,800 --> 00:15:03,080 AL development usually happens in Visual Studio Code. 420 00:15:03,080 --> 00:15:04,720 A-U often called VS Code. 421 00:15:04,720 --> 00:15:06,680 It's your workspace for writing AL files. 422 00:15:06,680 --> 00:15:08,240 It keeps your extension organized. 423 00:15:08,240 --> 00:15:09,840 It helps you find problems. 424 00:15:09,840 --> 00:15:11,200 And it sends the finished app 425 00:15:11,200 --> 00:15:13,120 to a business central environment for testing. 426 00:15:13,120 --> 00:15:15,880 But VS Code on its own is just a general code editor. 427 00:15:15,880 --> 00:15:18,440 It needs the AL language extension from Microsoft. 428 00:15:18,440 --> 00:15:21,480 That extension teaches VS Code how business central works. 429 00:15:21,480 --> 00:15:23,480 It can suggest object names as you type. 430 00:15:23,480 --> 00:15:25,400 It points out errors before you publish. 431 00:15:25,400 --> 00:15:27,360 It helps you browse fields and procedures. 432 00:15:27,360 --> 00:15:29,960 And it connects your project to a business central environment. 433 00:15:29,960 --> 00:15:31,280 That saves a lot of guesswork. 434 00:15:31,280 --> 00:15:34,240 When you start a new AL project, you can run the command AL. 435 00:15:34,240 --> 00:15:35,720 Go inside VS Code. 436 00:15:35,720 --> 00:15:38,200 It creates the basic project folder and settings files 437 00:15:38,200 --> 00:15:40,560 A-U extension name, publisher, version, 438 00:15:40,560 --> 00:15:42,880 and which business central environment to use. 439 00:15:42,880 --> 00:15:45,400 Think of that project folder as the extensions workbench. 440 00:15:45,400 --> 00:15:46,640 Each AL file belongs there. 441 00:15:46,640 --> 00:15:47,840 One file might hold a table. 442 00:15:47,840 --> 00:15:50,800 Another appage extension, a code unit can have its own file. 443 00:15:50,800 --> 00:15:52,600 That way, when someone opens the project, 444 00:15:52,600 --> 00:15:54,440 they can find the right part without scrolling 445 00:15:54,440 --> 00:15:55,920 through one huge document. 446 00:15:55,920 --> 00:15:57,240 When the code is ready to test, 447 00:15:57,240 --> 00:15:59,640 VS Code compiles it into an app package. 448 00:15:59,640 --> 00:16:01,720 That's the installable version of the extension. 449 00:16:01,720 --> 00:16:03,160 Business central reads that package 450 00:16:03,160 --> 00:16:05,200 and adds the extension to the environment. 451 00:16:05,200 --> 00:16:07,240 If there's a missing field, a spelling mistake, 452 00:16:07,240 --> 00:16:09,440 or any problem that prevents the app from building, 453 00:16:09,440 --> 00:16:12,760 VS Code tells you before the package ever reaches business central. 454 00:16:12,760 --> 00:16:14,480 Testing should happen in a sandbox first. 455 00:16:14,480 --> 00:16:16,840 A sandbox is a separate business central environment 456 00:16:16,840 --> 00:16:19,600 where you can try changes without risking live business work. 457 00:16:19,600 --> 00:16:21,560 You publish the extension, you open the pages, 458 00:16:21,560 --> 00:16:23,440 it changes, you enter test records, 459 00:16:23,440 --> 00:16:25,600 and you see if the rules work as expected. 460 00:16:25,600 --> 00:16:26,880 That separation matters. 461 00:16:26,880 --> 00:16:28,840 You don't want to discover that a new validation rule 462 00:16:28,840 --> 00:16:31,560 blocks sales orders while staff are trying to do their jobs. 463 00:16:31,560 --> 00:16:33,360 In a sandbox, you can make mistakes, 464 00:16:33,360 --> 00:16:36,120 remove test data, change code, and publish again 465 00:16:36,120 --> 00:16:37,640 without affecting live records. 466 00:16:37,640 --> 00:16:40,400 Sometimes the code runs, but the result still looks wrong. 467 00:16:40,400 --> 00:16:41,880 That's when debugging helps. 468 00:16:41,880 --> 00:16:44,560 You place a breakpoint in the code, start the process, 469 00:16:44,560 --> 00:16:46,720 and the extension pauses while it runs. 470 00:16:46,720 --> 00:16:49,280 At that pause, you can inspect values AL, 471 00:16:49,280 --> 00:16:51,760 like the current customer, the selected reward level, 472 00:16:51,760 --> 00:16:54,360 or the discount percentage the procedure calculated. 473 00:16:54,360 --> 00:16:56,160 Instead of guessing why a rule failed, 474 00:16:56,160 --> 00:16:58,240 you can see exactly what the code received. 475 00:16:58,240 --> 00:17:01,360 Development teams also use Git to keep a history of their work. 476 00:17:01,360 --> 00:17:04,000 Git records changes to the project files over time. 477 00:17:04,000 --> 00:17:06,440 If someone changes a rule and introduces a problem, 478 00:17:06,440 --> 00:17:08,840 the team can compare versions, see what changed, 479 00:17:08,840 --> 00:17:10,080 and revert if needed. 480 00:17:10,080 --> 00:17:12,400 It also helps when more than one developer works 481 00:17:12,400 --> 00:17:13,680 on the same extension. 482 00:17:13,680 --> 00:17:16,880 For a beginner, the best path is to start small. 483 00:17:16,880 --> 00:17:19,120 Learn your way around business central first. 484 00:17:19,120 --> 00:17:20,800 Then create one table and one page. 485 00:17:20,800 --> 00:17:24,080 After that, extend a standard page, add a simple business rule, 486 00:17:24,080 --> 00:17:26,880 and learn how events and install data fit into the project. 487 00:17:26,880 --> 00:17:30,480 Next, let's connect those pieces through one small add-on 488 00:17:30,480 --> 00:17:33,320 a business could actually use. 489 00:17:33,320 --> 00:17:36,840 A simple example, building a customer rewards add-on. 490 00:17:36,840 --> 00:17:39,000 What does a real AL extension actually look like? 491 00:17:39,000 --> 00:17:41,640 Let our thumbs dive into a simple example. 492 00:17:41,640 --> 00:17:43,960 Imagine your company wants customer reward levels, 493 00:17:43,960 --> 00:17:45,280 each with its own discount. 494 00:17:45,280 --> 00:17:47,120 You start by creating a reward table. 495 00:17:47,120 --> 00:17:49,720 Think of it as a digital filing cabinet, where each file 496 00:17:49,720 --> 00:17:53,040 holds an ID, a description, and a discount percentage. 497 00:17:53,040 --> 00:17:54,640 Gold gets 10% off, for instance. 498 00:17:54,640 --> 00:17:56,160 Your staff need to manage those levels 499 00:17:56,160 --> 00:17:57,720 without touching technical tools. 500 00:17:57,720 --> 00:17:59,800 So you add two pages, a reward list page 501 00:17:59,800 --> 00:18:03,160 to see all levels and a reward card page to edit or create one. 502 00:18:03,160 --> 00:18:05,320 They can add a new level, adjust a percentage, 503 00:18:05,320 --> 00:18:07,560 or review what's there or, or without opening 504 00:18:07,560 --> 00:18:08,720 any development environment. 505 00:18:08,720 --> 00:18:10,200 Next, you extend the customer table 506 00:18:10,200 --> 00:18:12,080 with a new field called reward ID. 507 00:18:12,080 --> 00:18:14,520 That field links each customer to one reward record. 508 00:18:14,520 --> 00:18:16,440 And you place that field right on the customer cart 509 00:18:16,440 --> 00:18:18,840 page where staff already manage customer details, 510 00:18:18,840 --> 00:18:21,520 then you add a reward action so they can open the reward list 511 00:18:21,520 --> 00:18:23,280 directly from that same cart. 512 00:18:23,280 --> 00:18:26,040 The discount rule itself lives inside a code unit. 513 00:18:26,040 --> 00:18:28,320 When another process needs a customer's discount, 514 00:18:28,320 --> 00:18:31,000 it calls that code unit instead of calculating it over 515 00:18:31,000 --> 00:18:32,200 and over on every page. 516 00:18:32,200 --> 00:18:33,040 That's efficient. 517 00:18:33,040 --> 00:18:35,120 An install code unit adds starter reward levels. 518 00:18:35,120 --> 00:18:36,960 The first time your extension is installed. 519 00:18:36,960 --> 00:18:39,480 And an event subscriber checks the chosen reward level 520 00:18:39,480 --> 00:18:41,800 during a sales process, applying your company's 521 00:18:41,800 --> 00:18:43,360 rule at exactly the right moment. 522 00:18:43,360 --> 00:18:46,400 That's one small extension, but notice what it contains. 523 00:18:46,400 --> 00:18:48,880 Data tables, user screens, navigation actions, 524 00:18:48,880 --> 00:18:51,560 setup logic, and business rules are all working together. 525 00:18:51,560 --> 00:18:52,920 That's the real power of AL. 526 00:18:52,920 --> 00:18:55,840 Well, conclusion, your AL development starting point. 527 00:18:55,840 --> 00:18:57,040 So here's the takeaway. 528 00:18:57,040 --> 00:18:59,760 AL development lets you add the specific features 529 00:18:59,760 --> 00:19:01,640 your company needs to business central 530 00:19:01,640 --> 00:19:03,720 without touching the core application. 531 00:19:03,720 --> 00:19:05,480 And you don't have to build everything at once. 532 00:19:05,480 --> 00:19:07,880 Start with one field, one page extension, 533 00:19:07,880 --> 00:19:08,960 and one clear rule. 534 00:19:08,960 --> 00:19:10,400 That's your first building block. 535 00:19:10,400 --> 00:19:12,320 If you found this knowledge nugget helpful, 536 00:19:12,320 --> 00:19:14,440 subscribe on your favorite podcast platform 537 00:19:14,440 --> 00:19:16,120 and share it with someone just starting out 538 00:19:16,120 --> 00:19:17,560 in business central development. 539 00:19:17,560 --> 00:19:20,080 Join us next time where we'll add another piece of the puzzle. 540 00:19:20,080 --> 00:19:22,400 I'm Mirko Peters, and this has been another episode 541 00:19:22,400 --> 00:19:25,680 of Microsoft Knowledge Nuggets on M365 FM.