{"id":1421,"date":"2011-11-21T18:21:45","date_gmt":"2011-11-22T01:21:45","guid":{"rendered":"https:\/\/simpleprogrammer.com\/?p=1421"},"modified":"2016-09-19T19:39:00","modified_gmt":"2016-09-19T23:39:00","slug":"understanding-the-vertical-slice","status":"publish","type":"post","link":"https:\/\/simpleprogrammer.com\/understanding-the-vertical-slice\/","title":{"rendered":"Understanding the Vertical Slice"},"content":{"rendered":"

One of the biggest challenges in breaking down backlogs is knowing how to split up the work from a backlog into right sized pieces.\\n\\nI\u2019ve already talked about the concept that smaller is better<\/a>, but I we haven\u2019t really addressed the decision of how to actually divide a backlog up to make it smaller.\\n\\n\"slice\"<\/a>\\n\\n<\/p>\n

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The default path<\/h2>\n

\\n\\nMost developers trying to break down a backlog into smaller chunks will automatically head down the path of using a \u201chorizontal slice.\u201d\\n\\n\"horizontal\"<\/a>\\n\\nThis is how we tend to think.\\n\\nWhat do I mean by a horizontal slice?\\n\\nA horizontal slice is basically a slice through the feature or backlog that horizontally divides up the architecture.\\n\\nMost things are built this way.\\n\\nIf you were to build a house, you would probably start by slicing up the project horizontally.\\n\\nYou would first pour the foundation.\u00a0 Then put up the walls.\u00a0 Then put on the roof and many more steps, leaving the finishing work for last.\\n\\nThis same thinking usually gets applied to breaking up backlogs in Agile development.\\n\\nIt would seem pretty silly to build a house where you finished one room completely at a time.\\n\\n<\/p>\n

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Agile software development is different<\/h2>\n

\\n\\nThere is a distinct difference though, between developing software in an Agile way and building a house.\\n\\nThe big difference is that in Agile software development, true Agile development, you don\u2019t know exactly what you are going to build until you are done building it.\\n\\nWith a house this is rarely the case.\\n\\nWith a house, you have some blueprints that you have drawn up ahead of time.\u00a0 You know exactly where each wall will be and where each outlet will be.\u00a0 You may have even built houses before that are very similar.\\n\\nWhen building software, unless you are taking a waterfall approach and planning everything upfront, you don\u2019t know what you are really building until you are done.\\n\\nBefore you object to this statement, consider this:\\n\\nThis is the point of Agile development.<\/strong>\\n\\nAgile means responding to change.\\n\\nBuilding a house, you do not expect the customer to say:\\n\\n\u201cHmm, yeah, I don\u2019t really like that wall there.\u201d\\n\\n\u201cActually, I am thinking we are going to need 5 bedrooms now.\u201d\\n\\nIn software development, you are expecting statements analogous to the above!\\n\\n<\/p>\n

So what is vertical slicing?<\/h2>\n

\\n\\nSimply put, building one room at a time.\\n\\nBut it\u2019s not functional!\u00a0 Who wants a house one room at a time?!?\\n\\nCorrect! It is not functional as a house, but we can pour more foundation, change how we are going to do the rest of the rooms and even knock down the walls and start over without incurring a huge cost.\\n\\nThe point in building our software \u201cone room at a time,\u201d is that we are giving the customer a chance to see the product as it is being built in a way that matters to them and enables them to test it out.\\n\\nSure they aren\u2019t going to be able to live in it until it is all done.\u00a0 But, they will have the ability to step into a room and envision it with all their furniture in there.\\n\\nCustomers don\u2019t care about foundations and framed in walls.\u00a0 As a developer, you might be able to look at some foundation and framed in walls and envision what the house will look like, but the customer can\u2019t and worse yet, it can\u2019t be tested.\\n\\nVertical slicing in software development is taking a backlog that might have some database component, some business logic and a user interface and breaking it down into small stepwise progressions where each step cuts through every slice.\\n\\nThe idea is that instead of breaking a backlog up into the following:\\n\\n<\/p>\n