SQLite Manager - Features

Features

SQLite implements most of the SQL-92 standard for SQL but it lacks some features. For example it has partial support for triggers, and it can't write to views (however it supports INSTEAD OF triggers that provide this functionality). While it supports complex queries, it still has limited ALTER TABLE support, as it can't modify or delete columns.

SQLite uses an unusual type system for an SQL-compatible DBMS. Instead of assigning a type to a column as in most SQL database systems, types are assigned to individual values; in language terms it is dynamically typed. Moreover, it is weakly typed in some of the same ways that Perl is: one can insert a string into an integer column (although SQLite will try to convert the string to an integer first, if the column's preferred type is integer). This adds flexibility to columns, especially when bound to a dynamically typed scripting language. However, the technique is not portable to other SQL products. A common criticism is that SQLite's type system lacks the data integrity mechanism provided by statically typed columns in other products. The SQLite web site describes a "strict affinity" mode, but this feature has not yet been added. However, it can be implemented with constraints like CHECK(typeof(x)='integer').

Several computer processes or threads may access the same database concurrently. Several read accesses can be satisfied in parallel. A write access can only be satisfied if no other accesses are currently being serviced. Otherwise, the write access fails with an error code (or can automatically be retried until a configurable timeout expires). This concurrent access situation would change when dealing with temporary tables. This restriction is relaxed in version 3.7 when WAL is turned on enabling concurrent reads and writes.

A standalone program called sqlite3 is provided that can be used to create a database, define tables within it, insert and change rows, run queries and manage an SQLite database file. This program is a single executable file on the host machine. It also serves as an example for writing applications that use the SQLite library.

SQLite is a popular choice for local/client SQL storage within a web browser and within a rich internet application framework; most notably the leaders in this area (Google Gears, Adobe AIR, and Firefox) embed SQLite.

SQLite full Unicode support is optional.

SQLite also has bindings for a large number of programming languages, including BASIC, C, C++, Clipper//Harbour, Common Lisp, C#, Curl, D, Delphi, Free Pascal, Haskell, Java, Livecode, Lua, newLisp, Objective-C (on OS X and iOS), OCaml, Perl, PHP, Pike, Python, REBOL, R, REALbasic, Ruby, Scheme, Smalltalk, Tcl, Visual Basic, and JavaScript. An ADO.NET adapter, initially developed by Robert Simpson, is maintained jointly with the SQLite developers since April 2010. An ODBC driver has been developed and is maintained separately by Christian Werner. Werner's ODBC driver is the recommend connection method for accessing SQLite from OpenOffice. There is also a COM (ActiveX) wrapper making SQLite accessible on Windows to scripted languages such as JScript and VBScript. This adds database capabilities to HTML Applications (HTA).

SQLite has automated regression testing prior to each release. Over 2 million tests are run as part of a release's verification. Starting with the August 10, 2009 release of SQLite 3.6.17, SQLite releases have 100% branch test coverage, one of the components of code coverage.