The "backing" field of a property is almost always private, since the idea of a property is to encapsulate all outside access to it. The syntax of parameters in queries is different per database system, but the differences are handled by TSQLQuery. Make it a function, not a property, if using it has a side effect or returns something random. The value of the property should not change unexpectedly. Again, the good convention is to make it behave like a constant, at least constant for this object instance with this state. The read-only properties are often used to make some field read-only from the outside. The application, build in this tutorial, should be able to perform the following database queries: Displaying information. All example programs mentioned in the documentation are available. They are located in the demo directory of the sources. FREE PASCAL SQLITE EXAMPLE CODE FREEThese programs have no other purpose than to demonstrate the capabilities of Free Pascal. The idea is that after M圜lass.MyProperty := 123 the programmer can expect that M圜lass.MyProperty = 123. A suite of demonstration programs comes included with the Free Pascal distribution. Do not convert or scale the requested value. Do not reject invalid values silently in the "setter" (raise an exception if you must). The setter function should always set the requested value, such that calling the getter yields it back. This is in fact one of the cool possibilities of a "getter" function. Note that it’s OK for getter to have some invisible side-effect, for example to cache a value of some calculation (known to produce the same results for given instance), to return it faster next time. It is open source, free, cross-platform, fast, reliable, and well supported. Using COM interfaces with reference-counting disabled SQLite is a small C library that has several advantages. FREE PASCAL SQLITE EXAMPLE CODE MACSQLite is used in the Solaris 10, Mac OS, Android, or in the iPhone. It is currently very popular and there are hundreds of millions copies worldwide in use today. Its developers call it a self-contained, serverless, zero-configuration, and transactional SQL database engine. More stuff inside classes and nested classes SQLite is an embedded relational database engine. Callbacks (aka events, aka pointers to functions, aka procedural variables) Containers (lists, dictionaries) using generics How the exceptions are displayed by various libraries Finally (doing things regardless if an exception occurred) Free notification observer (Castle Game Engine) Virtual methods, override and reintroduce Exposing one unit identifiers from another Enumerated and ordinal types and sets and constant-length arrays The TSQLite3Connection.CreateDB method inherited from the parent class actually does nothing to create a database if no file exists yet, you simply have to write table data as in the following example: (Code extracted from sqliteencryptionpragma example that ships with Lazarus 1. Testing single expression for multiple values (case) Logical, relational and bit-wise operators
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |