Merge pull request #1315 from stephencelis/schemachanger-create-table

Support creating tables in schema changer

Author: jberkel

Documentation/Index.md

@@ -63,6 +63,7 @@
       - [Renaming Columns](#renaming-columns)
       - [Dropping Columns](#dropping-columns)
       - [Renaming/Dropping Tables](#renamingdropping-tables)
+      - [Creating Tables](#creating-tables)      
     - [Indexes](#indexes)
       - [Creating Indexes](#creating-indexes)
       - [Dropping Indexes](#dropping-indexes)
@@ -1583,6 +1584,16 @@ try schemaChanger.rename(table: "users", to: "users_new")
 try schemaChanger.drop(table: "emails", ifExists: false)
 ```
 
+#### Creating Tables
+
+```swift
+let schemaChanger = SchemaChanger(connection: db)
+
+try schemaChanger.create(table: "users") { table in 
+    table.add(column: .init(name: "id", primaryKey: .init(autoIncrement: true), type: .INTEGER))
+    table.add(column: .init(name: "name", type: .TEXT, nullable: false))            
+} 
+
 ### Indexes
 
 

Makefile

@@ -35,7 +35,7 @@ lint: $(SWIFTLINT)
 	$< --strict
 
 lint-fix: $(SWIFTLINT)
-	$< lint fix
+	$< --fix
 
 clean:
 	$(XCODEBUILD) $(BUILD_ARGUMENTS) clean

Sources/SQLite/Schema/SchemaChanger.swift

@@ -43,19 +43,30 @@ public class SchemaChanger: CustomStringConvertible {
 
     public enum Operation {
         case addColumn(ColumnDefinition)
+        case addIndex(IndexDefinition, ifNotExists: Bool)
         case dropColumn(String)
+        case dropIndex(String, ifExists: Bool)
         case renameColumn(String, String)
         case renameTable(String)
+        case createTable(columns: [ColumnDefinition], ifNotExists: Bool)
 
         /// Returns non-nil if the operation can be executed with a simple SQL statement
         func toSQL(_ table: String, version: SQLiteVersion) -> String? {
             switch self {
             case .addColumn(let definition):
                 return "ALTER TABLE \(table.quote()) ADD COLUMN \(definition.toSQL())"
+            case .addIndex(let definition, let ifNotExists):
+                return definition.toSQL(ifNotExists: ifNotExists)
             case .renameColumn(let from, let to) where SQLiteFeature.renameColumn.isSupported(by: version):
                 return "ALTER TABLE \(table.quote()) RENAME COLUMN \(from.quote()) TO \(to.quote())"
             case .dropColumn(let column) where SQLiteFeature.dropColumn.isSupported(by: version):
                 return "ALTER TABLE \(table.quote()) DROP COLUMN \(column.quote())"
+            case .dropIndex(let name, let ifExists):
+                return "DROP INDEX \(ifExists ? " IF EXISTS " : "") \(name.quote())"
+            case .createTable(let columns, let ifNotExists):
+                return "CREATE TABLE \(ifNotExists ? " IF NOT EXISTS " : "") \(table.quote()) (" +
+                    columns.map { $0.toSQL() }.joined(separator: ", ") +
+                ")"
             default: return nil
             }
         }
@@ -89,7 +100,7 @@ public class SchemaChanger: CustomStringConvertible {
     public class AlterTableDefinition {
         fileprivate var operations: [Operation] = []
 
-        let name: String
+        public let name: String
 
         init(name: String) {
             self.name = name
@@ -99,21 +110,73 @@ public class SchemaChanger: CustomStringConvertible {
             operations.append(.addColumn(column))
         }
 
+        public func add(index: IndexDefinition, ifNotExists: Bool = false) {
+            operations.append(.addIndex(index, ifNotExists: ifNotExists))
+        }
+
         public func drop(column: String) {
             operations.append(.dropColumn(column))
         }
 
+        public func drop(index: String, ifExists: Bool = false) {
+            operations.append(.dropIndex(index, ifExists: ifExists))
+        }
+
         public func rename(column: String, to: String) {
             operations.append(.renameColumn(column, to))
         }
     }
 
+    public class CreateTableDefinition {
+        fileprivate var columnDefinitions: [ColumnDefinition] = []
+        fileprivate var indexDefinitions: [IndexDefinition] = []
+
+        let name: String
+        let ifNotExists: Bool
+
+        init(name: String, ifNotExists: Bool) {
+            self.name = name
+            self.ifNotExists = ifNotExists
+        }
+
+        public func add(column: ColumnDefinition) {
+            columnDefinitions.append(column)
+        }
+
+        public func add<T>(expression: Expression<T>) where T: Value {
+            add(column: .init(name: columnName(for: expression), type: .init(expression: expression), nullable: false))
+        }
+
+        public func add<T>(expression: Expression<T?>) where T: Value {
+            add(column: .init(name: columnName(for: expression), type: .init(expression: expression), nullable: true))
+        }
+
+        public func add(index: IndexDefinition) {
+            indexDefinitions.append(index)
+        }
+
+        var operations: [Operation] {
+            precondition(!columnDefinitions.isEmpty)
+            return [
+                .createTable(columns: columnDefinitions, ifNotExists: ifNotExists)
+            ] + indexDefinitions.map { .addIndex($0, ifNotExists: ifNotExists) }
+        }
+
+        private func columnName<T>(for expression: Expression<T>) -> String {
+            switch LiteralValue(expression.template) {
+            case .stringLiteral(let string): return string
+            default: fatalError("expression is not a literal string value")
+            }
+        }
+    }
+
     private let connection: Connection
     private let schemaReader: SchemaReader
     private let version: SQLiteVersion
     static let tempPrefix = "tmp_"
     typealias Block = () throws -> Void
     public typealias AlterTableDefinitionBlock = (AlterTableDefinition) -> Void
+    public typealias CreateTableDefinitionBlock = (CreateTableDefinition) -> Void
 
     struct Options: OptionSet {
         let rawValue: Int
@@ -141,6 +204,15 @@ public class SchemaChanger: CustomStringConvertible {
         }
     }
 
+    public func create(table: String, ifNotExists: Bool = false, block: CreateTableDefinitionBlock) throws {
+        let createTableDefinition = CreateTableDefinition(name: table, ifNotExists: ifNotExists)
+        block(createTableDefinition)
+
+        for operation in createTableDefinition.operations {
+            try run(table: table, operation: operation)
+        }
+    }
+
     public func drop(table: String, ifExists: Bool = true) throws {
         try dropTable(table, ifExists: ifExists)
     }
@@ -151,6 +223,12 @@ public class SchemaChanger: CustomStringConvertible {
         try connection.run("ALTER TABLE \(table.quote()) RENAME TO \(to.quote())")
     }
 
+    // Runs arbitrary SQL. Should only be used if no predefined operations exist.
+    @discardableResult
+    public func run(_ sql: String, _ bindings: Binding?...) throws -> Statement {
+        return try connection.run(sql, bindings)
+    }
+
     private func run(table: String, operation: Operation) throws {
         try operation.validate()
 
@@ -263,7 +341,9 @@ extension TableDefinition {
     func apply(_ operation: SchemaChanger.Operation?) -> TableDefinition {
         switch operation {
         case .none: return self
+        case .createTable, .addIndex, .dropIndex: fatalError()
         case .addColumn: fatalError("Use 'ALTER TABLE ADD COLUMN (...)'")
+
         case .dropColumn(let column):
             return TableDefinition(name: name,
                 columns: columns.filter { $0.name != column },
@@ -280,3 +360,13 @@ extension TableDefinition {
         }
     }
 }
+
+extension ColumnDefinition.Affinity {
+    init<T>(expression: Expression<T>) where T: Value {
+        self.init(T.declaredDatatype)
+    }
+
+    init<T>(expression: Expression<T?>) where T: Value {
+        self.init(T.declaredDatatype)
+    }
+}

Sources/SQLite/Schema/SchemaDefinitions.swift

@@ -93,7 +93,7 @@ public struct ColumnDefinition: Equatable {
         // swiftlint:disable:next force_try
         static let pattern = try! NSRegularExpression(pattern: "PRIMARY KEY\\s*(?:ASC|DESC)?\\s*(?:ON CONFLICT (\\w+)?)?\\s*(AUTOINCREMENT)?")
 
-        init(autoIncrement: Bool = true, onConflict: OnConflict? = nil) {
+        public init(autoIncrement: Bool = true, onConflict: OnConflict? = nil) {
             self.autoIncrement = autoIncrement
             self.onConflict = onConflict
         }
@@ -117,30 +117,46 @@ public struct ColumnDefinition: Equatable {
     }
 
     public struct ForeignKey: Equatable {
-        let table: String
-        let column: String
-        let primaryKey: String?
+        let fromColumn: String
+        let toTable: String
+        // when null, use primary key of "toTable"
+        let toColumn: String?
         let onUpdate: String?
         let onDelete: String?
+
+        public init(toTable: String, toColumn: String? = nil, onUpdate: String? = nil, onDelete: String? = nil) {
+            self.init(fromColumn: "", toTable: toTable, toColumn: toColumn, onUpdate: onUpdate, onDelete: onDelete)
+        }
+
+        public init(fromColumn: String, toTable: String, toColumn: String? = nil, onUpdate: String? = nil, onDelete: String? = nil) {
+            self.fromColumn = fromColumn
+            self.toTable = toTable
+            self.toColumn = toColumn
+            self.onUpdate = onUpdate
+            self.onDelete = onDelete
+        }
     }
 
     public let name: String
     public let primaryKey: PrimaryKey?
     public let type: Affinity
     public let nullable: Bool
+    public let unique: Bool
     public let defaultValue: LiteralValue
     public let references: ForeignKey?
 
     public init(name: String,
                 primaryKey: PrimaryKey? = nil,
                 type: Affinity,
                 nullable: Bool = true,
+                unique: Bool = false,
                 defaultValue: LiteralValue = .NULL,
                 references: ForeignKey? = nil) {
         self.name = name
         self.primaryKey = primaryKey
         self.type = type
         self.nullable = nullable
+        self.unique = unique
         self.defaultValue = defaultValue
         self.references = references
     }
@@ -244,16 +260,18 @@ public struct IndexDefinition: Equatable {
 
     public enum Order: String { case ASC, DESC }
 
-    public init(table: String, name: String, unique: Bool = false, columns: [String], `where`: String? = nil, orders: [String: Order]? = nil) {
+    public init(table: String, name: String, unique: Bool = false, columns: [String], `where`: String? = nil,
+                orders: [String: Order]? = nil, origin: Origin? = nil) {
         self.table = table
         self.name = name
         self.unique = unique
         self.columns = columns
         self.where = `where`
         self.orders = orders
+        self.origin = origin
     }
 
-    init (table: String, name: String, unique: Bool, columns: [String], indexSQL: String?) {
+    init (table: String, name: String, unique: Bool, columns: [String], indexSQL: String?, origin: Origin? = nil) {
         func wherePart(sql: String) -> String? {
             IndexDefinition.whereRe.firstMatch(in: sql, options: [], range: NSRange(location: 0, length: sql.count)).map {
                 (sql as NSString).substring(with: $0.range(at: 1))
@@ -270,12 +288,16 @@ public struct IndexDefinition: Equatable {
                         return memo2
             }
         }
+
+        let orders = indexSQL.flatMap(orders)
+
         self.init(table: table,
                   name: name,
                   unique: unique,
                   columns: columns,
                   where: indexSQL.flatMap(wherePart),
-                  orders: indexSQL.flatMap(orders))
+                  orders: (orders?.isEmpty ?? false) ? nil : orders,
+                  origin: origin)
     }
 
     public let table: String
@@ -284,6 +306,13 @@ public struct IndexDefinition: Equatable {
     public let columns: [String]
     public let `where`: String?
     public let orders: [String: Order]?
+    public let origin: Origin?
+
+    public enum Origin: String {
+        case uniqueConstraint = "u" // index created from a "CREATE TABLE (... UNIQUE)" column constraint
+        case createIndex = "c"      // index created explicitly via "CREATE INDEX ..."
+        case primaryKey = "pk"      // index created from a "CREATE TABLE PRIMARY KEY" column constraint
+    }
 
     enum IndexError: LocalizedError {
         case tooLong(String, String)
@@ -297,6 +326,13 @@ public struct IndexDefinition: Equatable {
         }
     }
 
+    // Indices with names of the form "sqlite_autoindex_TABLE_N" that are used to implement UNIQUE and PRIMARY KEY
+    // constraints on ordinary tables.
+    // https://sqlite.org/fileformat2.html#intschema
+    var isInternal: Bool {
+        name.starts(with: "sqlite_autoindex_")
+    }
+
     func validate() throws {
         if name.count > IndexDefinition.maxIndexLength {
             throw IndexError.tooLong(name, table)
@@ -345,6 +381,7 @@ extension ColumnDefinition {
             defaultValue.map { "DEFAULT \($0)" },
             primaryKey.map { $0.toSQL() },
             nullable ? nil : "NOT NULL",
+            unique ? "UNIQUE" : nil,
             references.map { $0.toSQL() }
         ].compactMap { $0 }
          .joined(separator: " ")
@@ -376,8 +413,8 @@ extension ColumnDefinition.ForeignKey {
     func toSQL() -> String {
         ([
             "REFERENCES",
-            table.quote(),
-            primaryKey.map { "(\($0.quote()))" },
+            toTable.quote(),
+            toColumn.map { "(\($0.quote()))" },
             onUpdate.map { "ON UPDATE \($0)" },
             onDelete.map { "ON DELETE \($0)" }
         ] as [String?]).compactMap { $0 }