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c# barcode generator library open source The Table in Font
The Table Data Matrix Generator In None Using Barcode creation for Font Control to generate, create DataMatrix image in Font applications. www.OnBarcode.comUSS-128 Generator In None Using Barcode generator for Font Control to generate, create GS1 128 image in Font applications. www.OnBarcode.comNext, we define the trait that holds the table itself. The Table trait takes a type parameter that is the type of the class that is implementing the trait. This type, MyType, will also be applied to fields and queries so that we can make sure that the only fields that are specified in queries to a particular table instance are fields defined by that table. We re also extending SuperTuple, which is a builder of Tuples that have extra type information. We ll get to that in a little while. Making ECC200 In None Using Barcode maker for Font Control to generate, create ECC200 image in Font applications. www.OnBarcode.comCreate QR Code In None Using Barcode generator for Font Control to generate, create Quick Response Code image in Font applications. www.OnBarcode.comtrait Table[MyType <: Table[MyType]] extends SuperTuple { this: MyType =>
Create UPC Code In None Using Barcode drawer for Font Control to generate, create Universal Product Code version A image in Font applications. www.OnBarcode.comPrinting Code 128A In None Using Barcode creation for Font Control to generate, create Code128 image in Font applications. www.OnBarcode.comA concrete instance of this trait must define the name of the database table.
Paint European Article Number 13 In None Using Barcode generation for Font Control to generate, create EAN13 image in Font applications. www.OnBarcode.comOneCode Drawer In None Using Barcode printer for Font Control to generate, create USPS OneCode Solution Barcode image in Font applications. www.OnBarcode.comdef table: String
Data Matrix ECC200 Maker In Objective-C Using Barcode encoder for iPhone Control to generate, create DataMatrix image in iPhone applications. www.OnBarcode.comData Matrix ECC200 Printer In Visual Studio .NET Using Barcode generator for Visual Studio .NET Control to generate, create Data Matrix ECC200 image in Visual Studio .NET applications. www.OnBarcode.comCHAPTER 7 TRAITS AND TYPES AND GNARLY STUFF FOR ARCHITECTS
Encode PDF-417 2d Barcode In VS .NET Using Barcode generation for Reporting Service Control to generate, create PDF417 image in Reporting Service applications. www.OnBarcode.comCode 3 Of 9 Maker In Visual Studio .NET Using Barcode printer for Reporting Service Control to generate, create Code 39 image in Reporting Service applications. www.OnBarcode.comAnd the instances must also define the type of the columns. This must be a Product. Product is the supertrait of all the Tuple classes. This does not give a lot of type safety standing on its own, because lots and lots of classes subclass from Product. However, you ll see how we make sure the type defined here ties to the actual fields, and the compiler will make sure that things are defined correctly. Drawing 2D Barcode In C#.NET Using Barcode drawer for VS .NET Control to generate, create Matrix Barcode image in VS .NET applications. www.OnBarcode.comPrinting Code 128 Code Set B In VS .NET Using Barcode creation for VS .NET Control to generate, create USS Code 128 image in VS .NET applications. www.OnBarcode.comtype ColumnTypes <: Product
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We re going to create a subtrait of BasicColumn that has a helper method, ~, that allows chaining of fields in definitions.9 So, you can write id ~ name ~ birthday as a definition of a Tuple of fields. These Tuples are special as they are subclasses of FieldProduct[MyType]. trait MyColumn[T] extends BasicColumn[MyType, T] { def ~[OT](p: MyColumn[OT]): MyTuple2[MyType, T, OT] = { val col = this new MyTuple2[MyType, T, OT](col.default, p.default) { def fields = List(col, p) def fieldProduct: (MyColumn[T], MyColumn[OT]) = (col, p) } } } The IntColumn is a column that holds an Int, has a default value, and can convert itself to and from JDBC. case class IntColumn(name: String) extends MyColumn[Int] { def default = 0 def set(st: PreparedStatement, offset: Int, value: Int) { st.setInt(offset, value) 9. In Scala, ~ is just a method. It s not a destructor like it is in C++.
CHAPTER 7 TRAITS AND TYPES AND GNARLY STUFF FOR ARCHITECTS
} def getField(rs: ResultSet): Int = rs.getInt(name) } And we now define column representations for Long, String, and Date: case class LongColumn(name: String) extends MyColumn[Long] { def default = 0 def set(st: PreparedStatement, offset: Int, value: Long) { st.setLong(offset, value) } def getField(rs: ResultSet): Long = rs.getLong(name) } case class StringColumn(name: String) extends MyColumn[String] { def default = "" def set(st: PreparedStatement, offset: Int, value: String) { st.setString(offset, value) } def getField(rs: ResultSet): String = rs.getString(name) } case class DateColumn(name: String) extends MyColumn[Date] { def default = new Date(0) def set(st: PreparedStatement, offset: Int, value: Date) { st.setDate(offset, new java.sql.Date(value.getTime)) } def getField(rs: ResultSet): Date = rs.getDate(name) } Previously, we ve defined the column types. Now, let s see how we define a method that can handle a query. The find method takes two parameters: the columns to return and the query parameters. You might call it as such: findCols(id ~ name, By(age, 33)). Such a call would return a List[(Int, String)]. Let s look at the type declaration. First we define the type parameter FT, which must be a Product with FieldProduct[MyType]. That means it s one of those nifty Tuples that can be constructed by chaining fields together with the ~. The first parameter, cols, must be an FT. That means that the cols parameter is composed of fields that represent columns in the current table. The return type is the ReturnType type on FieldProduct, which will be the column types.
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