DB tutorial using Database.NET dbforge Studio Express and SQLiteSpy

Transcription

1 DB tutorial using Database.NET dbforge Studio Express and SQLiteSpy

2 SQLite SQLite is a open source file-based database which used in a lot of applications on both desktop and mobile It is easy to play around with and since it works more or less as the real RDBMS you can transfer your SQL logic from the playground to your application SQLiteSpy is one of many graphical environments one can use to play with SQLite.db3 files To create a table, we give a name to a table and to its columns. Each column can have one of these data types NULL - The value is a NULL value INTEGER - a signed integer REAL - a floating point value TEXT - a text string BLOB - a blob of data

3 Creating SQLite tables Make a database (File > New Database) and save Insert SQL table creation and press F9

4 Creating SQLite data Note that PRIMARY KEY is AUTOINCREMENT by default

5 View the.db3 files content Viewing the tables one can see: Column names, Type (data type), NN (not null), PK (primary key) and default value

6 SQL querys Enter a valid SQL query and hit F9 to view results The t1 value is an alias for Artists

7 World DB bundled with SQLiteSpy

8 dbforge Studio Express for MySQL

9 Using dbforge 1

10 Using dbforge 2

11 Using dbforge - Query builder

12 Using dbforge - Query builder

13 Database.NET

14 Using Database.NET Create additional table songs and add some data

15 Query multiple tables 1 SELECT with FROM AND WHERE SELECT table1.column1, table2.column2 FROM table1, table2 WHERE table1.column1 = table2.column1; SELECT table1.column1, table2.column2 FROM table1, table2, table3 WHERE table1.column1 = table2.column1 AND table1.column1 = table3.column1; Select All CDs from Peter Gabriel - artistid = 1 SELECT * FROM artists, cds WHERE artists.artistid = cds.artistid and artists.artistid = 1 SELECT * FROM artists, cds WHERE artists.artistid = cds.artistid and artists.artistname ='Peter Gabriel'; All songs from Peter Gabriel - artistid = 1 SELECT * FROM artists, cds, songs WHERE artists.artistid = cds.artistid and cds.cdid = songs.cdid and artists.artistid = 1 SELECT * FROM artists, cds, songs WHERE artists.artistid = cds.artistid and cds.cdid = songs.cdid and artists.artistname ='Peter Gabriel';

16 Query multiple tables 2 Subqueries, or subselect statements, are a way to use a result set as a resource in a query SELECT column1 FROM table1 WHERE EXISTS ( SELECT column1 FROM table2 WHERE table1.column1 = table2.column1 ) [optional query parameters]; Nested select where exists All artists with a CD SELECT Artistname FROM Artists WHERE EXISTS ( SELECT cdid FROM cds WHERE artists.artistid = cds.artistid); All cd albums with songs SELECT title FROM cds WHERE EXISTS ( SELECT cdid FROM songs WHERE cds.cdid = songs.cdid ); All artists with songs SELECT artistname FROM artists WHERE EXISTS ( SELECT cds.cdid FROM songs, cds WHERE cds.cdid = songs.cdid and artists.artistid = cds.artistid); All artists with name Peter Gabriel SELECT artistname FROM artists WHERE EXISTS ( SELECT cds.cdid FROM songs, cds WHERE cds.cdid = songs.cdid and artists.artistid = cds.artistid) and artistname='peter Gabriel';

17 Query multiple tables 3 JOIN works in the same way as select SELECT table1.column1, table2.column2 FROM table1 INNER JOIN table2 ON table1.column1 = table2.column1; An INNER JOIN will only return rows for which there is data in both tables, OUTER JOIN will not There are several types of JOIN - LEFT, RIGHT, and FULL OUTER; INNER; and CROSS. Inner Join cds for all artists SELECT artists.*, cds.* FROM artists INNER JOIN cds ON artists.artistid = cds.artistid; cds for a artist SELECT artists.*, cds.* FROM artists INNER JOIN cds ON artists.artistid = cds.artistid where artistname = 'Bruce Hornsby'; All rows SELECT artists.*, cds.*, songs.* FROM artists INNER JOIN cds ON artists.artistid = cds.artistid JOIN songs on cds.cdid = songs.cdid; Get the first track on all cds SELECT artists.*, cds.*, songs.* FROM artists INNER JOIN cds ON artists.artistid = cds.artistid JOIN songs on cds.cdid = songs.cdid where songs.tracknr=1;

18 Links and references DB tutorial I made with 3 tables, Artists, Cds and Songs Mini SQL-tutorial.pdf Nwind.mdb is bundled with Access and can be played with, connect with Database.NET SQL basics: Query multiple tables Compilation of MySQL GUI Tools