Initial development of new SQLite-based database for iOS app.

Adapt existing schema and demo data to the database and implement import.
New setup screen design
Performance testing - able to import entire demo database in 100ms, and export the ENTIRE database to a sync json in 300ms

MemriDatabase.xcodeproj/project.pbxproj

@@ -3,10 +3,21 @@
 	archiveVersion = 1;
 	classes = {
 	};
-	objectVersion = 50;
+	objectVersion = 52;
 	objects = {
 
 /* Begin PBXBuildFile section */
+		D714F284255AAD100072FE97 /* DatabaseController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D714F283255AAD100072FE97 /* DatabaseController.swift */; };
+		D714F28A255AAD890072FE97 /* GRDB in Frameworks */ = {isa = PBXBuildFile; productRef = D714F289255AAD890072FE97 /* GRDB */; };
+		D7362AAF257C81ED009F540F /* String.swift in Sources */ = {isa = PBXBuildFile; fileRef = D7362AAE257C81ED009F540F /* String.swift */; };
+		D7362AB7257C822A009F540F /* ActivityIndicatorView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D7362AB6257C822A009F540F /* ActivityIndicatorView.swift */; };
+		D73BA2492574C1220025C753 /* schema.json in Resources */ = {isa = PBXBuildFile; fileRef = D73BA2482574C1220025C753 /* schema.json */; };
+		D73BA24E2574C1300025C753 /* Schema.swift in Sources */ = {isa = PBXBuildFile; fileRef = D73BA24D2574C1300025C753 /* Schema.swift */; };
+		D73BA2532574CA2F0025C753 /* DemoData.swift in Sources */ = {isa = PBXBuildFile; fileRef = D73BA2522574CA2F0025C753 /* DemoData.swift */; };
+		D73BA2582574CA460025C753 /* demo_database.json in Resources */ = {isa = PBXBuildFile; fileRef = D73BA2572574CA460025C753 /* demo_database.json */; };
+		D745D1622575C39D006BC24D /* SyncController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D745D1612575C39D006BC24D /* SyncController.swift */; };
+		D76EA501255DF01500AE2E20 /* DatabaseTypes.swift in Sources */ = {isa = PBXBuildFile; fileRef = D76EA500255DF01500AE2E20 /* DatabaseTypes.swift */; };
+		D7A135C5257B562600EBEEF7 /* SetupScreen.swift in Sources */ = {isa = PBXBuildFile; fileRef = D7A135C4257B562600EBEEF7 /* SetupScreen.swift */; };
 		D7F136F8254E645D00881B25 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = D7F136F7254E645D00881B25 /* AppDelegate.swift */; };
 		D7F136FA254E645D00881B25 /* SceneDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = D7F136F9254E645D00881B25 /* SceneDelegate.swift */; };
 		D7F136FC254E645D00881B25 /* ContentView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D7F136FB254E645D00881B25 /* ContentView.swift */; };
@@ -35,6 +46,16 @@
 /* End PBXContainerItemProxy section */
 
 /* Begin PBXFileReference section */
+		D714F283255AAD100072FE97 /* DatabaseController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DatabaseController.swift; sourceTree = "<group>"; };
+		D7362AAE257C81ED009F540F /* String.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = String.swift; sourceTree = "<group>"; };
+		D7362AB6257C822A009F540F /* ActivityIndicatorView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ActivityIndicatorView.swift; sourceTree = "<group>"; };
+		D73BA2482574C1220025C753 /* schema.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = schema.json; sourceTree = "<group>"; };
+		D73BA24D2574C1300025C753 /* Schema.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Schema.swift; sourceTree = "<group>"; };
+		D73BA2522574CA2F0025C753 /* DemoData.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DemoData.swift; sourceTree = "<group>"; };
+		D73BA2572574CA460025C753 /* demo_database.json */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.json; path = demo_database.json; sourceTree = "<group>"; };
+		D745D1612575C39D006BC24D /* SyncController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SyncController.swift; sourceTree = "<group>"; };
+		D76EA500255DF01500AE2E20 /* DatabaseTypes.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DatabaseTypes.swift; sourceTree = "<group>"; };
+		D7A135C4257B562600EBEEF7 /* SetupScreen.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SetupScreen.swift; sourceTree = "<group>"; };
 		D7F136F4254E645D00881B25 /* MemriDatabase.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = MemriDatabase.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		D7F136F7254E645D00881B25 /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
 		D7F136F9254E645D00881B25 /* SceneDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SceneDelegate.swift; sourceTree = "<group>"; };
@@ -56,6 +77,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				D714F28A255AAD890072FE97 /* GRDB in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -76,6 +98,94 @@
 /* End PBXFrameworksBuildPhase section */
 
 /* Begin PBXGroup section */
+		D7362AAD257C81DB009F540F /* Extensions */ = {
+			isa = PBXGroup;
+			children = (
+				D7362AAE257C81ED009F540F /* String.swift */,
+			);
+			path = Extensions;
+			sourceTree = "<group>";
+		};
+		D7A135B7257B55EC00EBEEF7 /* Database */ = {
+			isa = PBXGroup;
+			children = (
+				D7A135BF257B560700EBEEF7 /* Local */,
+				D7A135BB257B55FE00EBEEF7 /* Syncing */,
+			);
+			path = Database;
+			sourceTree = "<group>";
+		};
+		D7A135BB257B55FE00EBEEF7 /* Syncing */ = {
+			isa = PBXGroup;
+			children = (
+				D745D1612575C39D006BC24D /* SyncController.swift */,
+			);
+			path = Syncing;
+			sourceTree = "<group>";
+		};
+		D7A135BF257B560700EBEEF7 /* Local */ = {
+			isa = PBXGroup;
+			children = (
+				D714F283255AAD100072FE97 /* DatabaseController.swift */,
+				D76EA500255DF01500AE2E20 /* DatabaseTypes.swift */,
+				D73BA24D2574C1300025C753 /* Schema.swift */,
+				D73BA2522574CA2F0025C753 /* DemoData.swift */,
+			);
+			path = Local;
+			sourceTree = "<group>";
+		};
+		D7A135C3257B561500EBEEF7 /* UI */ = {
+			isa = PBXGroup;
+			children = (
+				D7A135C9257B564900EBEEF7 /* Setup */,
+				D7A135CA257B565000EBEEF7 /* Navigation */,
+				D7A135CB257B565D00EBEEF7 /* Settings */,
+				D7A135CC257B566800EBEEF7 /* Components */,
+			);
+			path = UI;
+			sourceTree = "<group>";
+		};
+		D7A135C9257B564900EBEEF7 /* Setup */ = {
+			isa = PBXGroup;
+			children = (
+				D7A135C4257B562600EBEEF7 /* SetupScreen.swift */,
+			);
+			path = Setup;
+			sourceTree = "<group>";
+		};
+		D7A135CA257B565000EBEEF7 /* Navigation */ = {
+			isa = PBXGroup;
+			children = (
+			);
+			path = Navigation;
+			sourceTree = "<group>";
+		};
+		D7A135CB257B565D00EBEEF7 /* Settings */ = {
+			isa = PBXGroup;
+			children = (
+			);
+			path = Settings;
+			sourceTree = "<group>";
+		};
+		D7A135CC257B566800EBEEF7 /* Components */ = {
+			isa = PBXGroup;
+			children = (
+				D7362AB6257C822A009F540F /* ActivityIndicatorView.swift */,
+			);
+			path = Components;
+			sourceTree = "<group>";
+		};
+		D7A135CD257B567A00EBEEF7 /* Assets */ = {
+			isa = PBXGroup;
+			children = (
+				D7F13702254E645E00881B25 /* LaunchScreen.storyboard */,
+				D7F136FD254E645E00881B25 /* Assets.xcassets */,
+				D73BA2482574C1220025C753 /* schema.json */,
+				D73BA2572574CA460025C753 /* demo_database.json */,
+			);
+			path = Assets;
+			sourceTree = "<group>";
+		};
 		D7F136EB254E645D00881B25 = {
 			isa = PBXGroup;
 			children = (
@@ -102,8 +212,10 @@
 				D7F136F7254E645D00881B25 /* AppDelegate.swift */,
 				D7F136F9254E645D00881B25 /* SceneDelegate.swift */,
 				D7F136FB254E645D00881B25 /* ContentView.swift */,
-				D7F136FD254E645E00881B25 /* Assets.xcassets */,
-				D7F13702254E645E00881B25 /* LaunchScreen.storyboard */,
+				D7A135B7257B55EC00EBEEF7 /* Database */,
+				D7A135C3257B561500EBEEF7 /* UI */,
+				D7362AAD257C81DB009F540F /* Extensions */,
+				D7A135CD257B567A00EBEEF7 /* Assets */,
 				D7F13705254E645E00881B25 /* Info.plist */,
 				D7F136FF254E645E00881B25 /* Preview Content */,
 			);
@@ -152,6 +264,9 @@
 			dependencies = (
 			);
 			name = MemriDatabase;
+			packageProductDependencies = (
+				D714F289255AAD890072FE97 /* GRDB */,
+			);
 			productName = MemriDatabase;
 			productReference = D7F136F4254E645D00881B25 /* MemriDatabase.app */;
 			productType = "com.apple.product-type.application";
@@ -223,6 +338,9 @@
 				Base,
 			);
 			mainGroup = D7F136EB254E645D00881B25;
+			packageReferences = (
+				D714F288255AAD890072FE97 /* XCRemoteSwiftPackageReference "GRDB" */,
+			);
 			productRefGroup = D7F136F5254E645D00881B25 /* Products */;
 			projectDirPath = "";
 			projectRoot = "";
@@ -239,7 +357,9 @@
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				D73BA2492574C1220025C753 /* schema.json in Resources */,
 				D7F13704254E645E00881B25 /* LaunchScreen.storyboard in Resources */,
+				D73BA2582574CA460025C753 /* demo_database.json in Resources */,
 				D7F13701254E645E00881B25 /* Preview Assets.xcassets in Resources */,
 				D7F136FE254E645E00881B25 /* Assets.xcassets in Resources */,
 			);
@@ -266,8 +386,16 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				D7A135C5257B562600EBEEF7 /* SetupScreen.swift in Sources */,
+				D745D1622575C39D006BC24D /* SyncController.swift in Sources */,
+				D7362AAF257C81ED009F540F /* String.swift in Sources */,
+				D73BA24E2574C1300025C753 /* Schema.swift in Sources */,
 				D7F136F8254E645D00881B25 /* AppDelegate.swift in Sources */,
+				D73BA2532574CA2F0025C753 /* DemoData.swift in Sources */,
+				D7362AB7257C822A009F540F /* ActivityIndicatorView.swift in Sources */,
+				D76EA501255DF01500AE2E20 /* DatabaseTypes.swift in Sources */,
 				D7F136FA254E645D00881B25 /* SceneDelegate.swift in Sources */,
+				D714F284255AAD100072FE97 /* DatabaseController.swift in Sources */,
 				D7F136FC254E645D00881B25 /* ContentView.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -597,6 +725,25 @@
 			defaultConfigurationName = Release;
 		};
 /* End XCConfigurationList section */
+
+/* Begin XCRemoteSwiftPackageReference section */
+		D714F288255AAD890072FE97 /* XCRemoteSwiftPackageReference "GRDB" */ = {
+			isa = XCRemoteSwiftPackageReference;
+			repositoryURL = "https://github.com/groue/GRDB.swift";
+			requirement = {
+				kind = upToNextMajorVersion;
+				minimumVersion = 5.1.0;
+			};
+		};
+/* End XCRemoteSwiftPackageReference section */
+
+/* Begin XCSwiftPackageProductDependency section */
+		D714F289255AAD890072FE97 /* GRDB */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = D714F288255AAD890072FE97 /* XCRemoteSwiftPackageReference "GRDB" */;
+			productName = GRDB;
+		};
+/* End XCSwiftPackageProductDependency section */
 	};
 	rootObject = D7F136EC254E645D00881B25 /* Project object */;
 }

MemriDatabase.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

+{
+  "object": {
+    "pins": [
+      {
+        "package": "GRDB",
+        "repositoryURL": "https://github.com/groue/GRDB.swift",
+        "state": {
+          "branch": null,
+          "revision": "2c51c047081da160698e818d6844af75f321f867",
+          "version": "5.1.0"
+        }
+      }
+    ]
+  },
+  "version": 1
+}

MemriDatabase.xcodeproj/project.xcworkspace/xcuserdata/tbrennan.xcuserdatad/IDEFindNavigatorScopes.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<array/>
+</plist>

MemriDatabase.xcodeproj/xcuserdata/tbrennan.xcuserdatad/xcdebugger/Breakpoints_v2.xcbkptlist

+<?xml version="1.0" encoding="UTF-8"?>
+<Bucket
+   uuid = "A27FE82B-1838-4084-929E-9C9323F7E4D2"
+   type = "1"
+   version = "2.0">
+   <Breakpoints>
+      <BreakpointProxy
+         BreakpointExtensionID = "Xcode.Breakpoint.FileBreakpoint">
+         <BreakpointContent
+            uuid = "4CE36434-2BB7-4DDC-BB72-9093FC1A9047"
+            shouldBeEnabled = "Yes"
+            ignoreCount = "0"
+            continueAfterRunningActions = "No"
+            filePath = "MemriDatabase/DemoData.swift"
+            startingColumnNumber = "9223372036854775807"
+            endingColumnNumber = "9223372036854775807"
+            startingLineNumber = "54"
+            endingLineNumber = "54"
+            landmarkName = "test()"
+            landmarkType = "9">
+         </BreakpointContent>
+      </BreakpointProxy>
+   </Breakpoints>
+</Bucket>

MemriDatabase.xcodeproj/xcuserdata/tbrennan.xcuserdatad/xcschemes/xcschememanagement.plist

@@ -4,8 +4,160 @@
 <dict>
 	<key>SchemeUserState</key>
 	<dict>
+		<key>Associations (Playground) 1.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>5</integer>
+		</dict>
+		<key>Associations (Playground) 2.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>6</integer>
+		</dict>
+		<key>Associations (Playground).xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>4</integer>
+		</dict>
+		<key>CustomizedDecodingOfDatabaseRows (Playground) 1.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>14</integer>
+		</dict>
+		<key>CustomizedDecodingOfDatabaseRows (Playground) 2.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>15</integer>
+		</dict>
+		<key>CustomizedDecodingOfDatabaseRows (Playground).xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>13</integer>
+		</dict>
+		<key>Format Code.xcscheme_^#shared#^_</key>
+		<dict>
+			<key>orderHint</key>
+			<integer>19</integer>
+		</dict>
+		<key>GettingStarted (Playground) 1.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>17</integer>
+		</dict>
+		<key>GettingStarted (Playground) 2.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>18</integer>
+		</dict>
+		<key>GettingStarted (Playground) 3.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>2</integer>
+		</dict>
+		<key>GettingStarted (Playground) 4.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>5</integer>
+		</dict>
+		<key>GettingStarted (Playground) 5.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>6</integer>
+		</dict>
+		<key>GettingStarted (Playground).xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>16</integer>
+		</dict>
 		<key>MemriDatabase.xcscheme_^#shared#^_</key>
 		<dict>
+			<key>orderHint</key>
+			<integer>1</integer>
+		</dict>
+		<key>MyPlayground (Playground) 1.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>11</integer>
+		</dict>
+		<key>MyPlayground (Playground) 2.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>12</integer>
+		</dict>
+		<key>MyPlayground (Playground).xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>10</integer>
+		</dict>
+		<key>Tour (Playground) 1.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>8</integer>
+		</dict>
+		<key>Tour (Playground) 2.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>9</integer>
+		</dict>
+		<key>Tour (Playground).xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>7</integer>
+		</dict>
+		<key>TransactionObserver (Playground) 1.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>2</integer>
+		</dict>
+		<key>TransactionObserver (Playground) 2.xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
+			<key>orderHint</key>
+			<integer>3</integer>
+		</dict>
+		<key>TransactionObserver (Playground).xcscheme</key>
+		<dict>
+			<key>isShown</key>
+			<false/>
 			<key>orderHint</key>
 			<integer>0</integer>
 		</dict>

MemriDatabase/AppDelegate.swift

@@ -13,7 +13,39 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
 
 
     func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
-        // Override point for customization after application launch.
+        DatabaseController.shared.setupDatabase()
+        importDemoData()
+        try! SyncController.shared.syncUpload(maxItems: 1000000)
+//        try! SyncController.shared.syncDownload(json: (
+//        """
+//        {
+//          "update" : [
+//            {
+//              "testProperty1" : "testing",
+//              "dateModified" : 1606787421852,
+//              "uid" : "E2662EE0-254B-48BC-B097-85B6E2F51F99",
+//              "version" : 1,
+//              "dateCreated" : 1606787421852,
+//              "deleted" : false
+//            }
+//          ],
+//          "create" : [
+//            {
+//              "dateModified" : 1606787421850,
+//              "testPropertyNumber" : 542.13999999999999,
+//              "dateCreated" : 1606787421850,
+//              "uid" : "D7C756C6-3EEA-4DBC-AE25-F06DE5B56BA8",
+//              "version" : 1,
+//              "testProperty2" : "test this out",
+//              "testPropertyDate" : 1606787421853,
+//              "deleted" : false,
+//              "testProperty1" : "ok tastedsc"
+//            }
+//          ]
+//        }
+//        """.data(using: .utf8)!))
+        
+        
         return true
     }
 

MemriDatabase/ContentView.swift

@@ -9,8 +9,7 @@ import SwiftUI
 
 struct ContentView: View {
     var body: some View {
-        Text("Hello, world!")
-            .padding()
+        SetupScreen()
     }
 }
 

MemriDatabase/Database/Local/DatabaseController.swift

+//
+//  GRDBTest.swift
+//  MemriDatabase
+//
+//  Created by T Brennan on 10/11/20.
+//
+
+import Foundation
+import GRDB
+
+class DatabaseController {
+    static let shared = DatabaseController()
+    
+    let databasePool: DatabasePool =  {
+        let paths = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)
+        let documentsDirectory = paths[0]
+        let url = documentsDirectory.appendingPathComponent("memri.sqlite")
+        print(url)
+        return try! DatabasePool(path: url.path)
+    }()
+    
+    var schema = Schema.loadFromFile()
+    
+    func setupDatabase() {
+        var migrator = DatabaseMigrator()
+        
+        #if DEBUG
+        try! databasePool.erase()
+        // Speed up development by wiping the database when migrations change
+        // NEVER set this outside of debug mode (because it deletes everything)
+        migrator.eraseDatabaseOnSchemaChange = true
+        #endif
+        
+        migrator.registerMigration("initialSetup") { db in
+            try db.create(table: "item") { t in
+                // 16 byte UUID that uniquely identifies this item
+                t.column("uid", .text).notNull().primaryKey()
+                
+                // The type of this item (a string matching a type defined in the schema)
+                t.column("type", .text).notNull()
+                
+                // Time of creation
+                t.column("dateCreated", .integer).notNull()
+                
+                // Time last modified
+                t.column("dateModified", .integer).notNull()
+                
+                // Version - starts at 1
+                t.column("version", .integer).defaults(to: 1).notNull(onConflict: .replace)
+                
+                // Whether this item has been deleted (default = false)
+                t.column("deleted", .boolean).defaults(to: false).notNull(onConflict: .replace)
+                
+                // iOS only (used for syncing decisions
+                t.column("syncState", .text).defaults(to: SyncState.create).notNull(onConflict: .replace)
+                t.column("syncHasPriority", .boolean).defaults(to: false).notNull(onConflict: .replace)
+            }
+            
+            try db.create(table: "itemEdge") { t in
+                // The uid of the item this edge belongs to. Delete this row if the item is deleted
+                t.column("ownerUID", .blob).notNull().indexed().references("item", onDelete: .cascade)
+                
+                // The name of this edge
+                t.column("name", .text).notNull()
+                
+                // The target item of this edge. Delete this row if the target item is deleted
+                t.column("targetUID", .blob).notNull().indexed().references("item", onDelete: .cascade)
+            }
+            
+            try db.create(table: "itemProperty") { t in
+                // The uid of the item this property belongs to. Delete this row if the item is deleted
+                t.column("itemUID", .blob).notNull().indexed().references("item", onDelete: .cascade)
+                
+                // The name of this property
+                t.column("name", .text).notNull()
+                
+                // The value of this property
+                t.column("value", .blob).notNull()
+                
+                // There must be only one row for each property name per item - if we try to add another replace the old one
+                t.uniqueKey(["itemUID", "name"], onConflict: .replace)
+            }
+            
+            try db.create(virtualTable: "itemProperty_search", using: FTS4()) { t in
+                t.synchronize(withTable: "itemProperty")
+                t.tokenizer = .porter
+                t.column("itemUID").notIndexed()
+                t.column("name").notIndexed()
+                t.column("value")
+            }
+        }
+        
+        try! migrator.migrate(databasePool)
+    }
+    
+    func searchTest() {
+        try! databasePool.read { (db) in
+            let searchQuery = FTS3Pattern(matchingAllTokensIn: "testing out")!
+            let refinedQuery = try! FTS3Pattern(rawPattern: "\(searchQuery.rawPattern)*")
+            let search = try! ItemRecord.search(db, pattern: refinedQuery)
+            print(search)
+        }
+    }
+}
+

MemriDatabase/Database/Syncing/SyncController.swift

+//
+//  SyncController.swift
+//  MemriDatabase
+//
+//  Created by T Brennan on 1/12/20.
+//
+
+import Foundation
+import GRDB
+
+enum SyncState: String, Codable, Hashable, DatabaseValueConvertible {
+    case create
+    case update
+    case noChanges
+    case failed
+}
+
+class SyncController {
+    static let shared = SyncController()
+    
+    let databaseController: DatabaseController = DatabaseController.shared
+    
+    
+    func syncUpload(maxItems: Int = 100) throws {
+        #if DEBUG
+        let startTime = CFAbsoluteTimeGetCurrent()
+        #endif
+        // Construct the JSON to send to the pod
+        let syncJsonData = try databaseController.databasePool.read { (db) -> Data in
+            
+            /// Select the items to sync, giving priority to those marked as `syncHasPriority`
+            let itemsForSync = try ItemRecord.order(ItemRecord.Columns.syncHasPriority.desc).limit(maxItems).fetchAll(db).filter { ![SyncState.noChanges, SyncState.failed].contains($0.syncState) }
+            
+            /// Construct a JSON-compatible representation for the items
+            let syncItems = itemsForSync.map { itemRecord -> SyncUploadItem in
+                let properties = itemRecord.syncDict(db: db)
+                return SyncUploadItem(operation: itemRecord.syncState, properties: properties)
+            }
+            
+            /// Group by sync operation. eg. create, update
+            let itemsByOperation = Dictionary(grouping: syncItems) { $0.operation.rawValue }.mapValues { $0.map { $0.properties } }
+            
+            return try JSONSerialization.data(withJSONObject: itemsByOperation, options: [.prettyPrinted])
+        }
+        #if DEBUG
+        let timeElapsed = CFAbsoluteTimeGetCurrent() - startTime
+        print("Time elapsed to make sync JSON: \(timeElapsed) s.")
+        #endif
+        
+        #if DEBUG
+        let writePath = "/Users/tbrennan/syncOutput.json"
+        try! syncJsonData.write(to: URL(fileURLWithPath: writePath))
+        #endif
+        
+        // Start network task
+        
+        // Handle network task completion (eg. mark items as synced or failed)
+        
+        // Schedule another sync operation until all batches are complete
+    }
+    
+    func syncDownload(json: Data) throws {
+        guard let dict = try JSONSerialization.jsonObject(with: json, options: []) as? [String: [[String: Any?]]] else {
+            // Throw here
+            return
+        }
+        let createItemDicts = dict[SyncState.create.rawValue] ?? []
+        let updateItemsDicts = dict[SyncState.update.rawValue] ?? []
+        
+        let createItems = createItemDicts.compactMap(SyncDownloadItem.init)
+        let updateItems = updateItemsDicts.compactMap(SyncDownloadItem.init)
+        
+        print("Sync download test: Create \(createItems.count) items, Update \(updateItems.count) items")
+    }
+}
+
+struct SyncUploadItem {
+    var operation: SyncState
+    var properties: [String: Any?]
+}
+
+struct SyncDownloadItem {
+    var item: ItemRecord
+    var properties: [ItemPropertyRecord]
+    
+    init?(fromSyncItemDict dict: [String: Any?]) {
+        guard let item = try? ItemRecord(fromSyncDict: dict) else { return nil }
+        let properties = dict.filter { !ItemRecord.intrinsicProperties.contains($0.key) }
+            .compactMap { property in
+                ItemPropertyRecord(itemUID: item.uid, name: property.key, value: property.value)
+            }
+        self.item = item
+        self.properties = properties
+    }
+}