Support multiple licenses per package

Split out package licenses into two separate tables in order to support
multiple licenses per package. The code on the package details page is
adjusted accordingly.

UPGRADING contains instructions on how to convert existing licenses in
the database to the new layout.

Signed-off-by: Lukas Fleischer <archlinux@cryptocrack.de>

1 files changed, 33 insertions, 0 deletions

diff --git a/UPGRADING b/UPGRADING
index 814fea1a..357cd6c7 100644
--- a/UPGRADING
+++ b/UPGRADING
@@ -217,6 +217,39 @@ CREATE TABLE PackageGroups (
 ) ENGINE = InnoDB;
 ----
 
+18. Create tables to store package licenses:
+
+----
+CREATE TABLE Licenses (
+	ID INTEGER UNSIGNED NOT NULL AUTO_INCREMENT,
+	Name VARCHAR(64) NOT NULL,
+	PRIMARY KEY (ID),
+	UNIQUE (Name)
+) ENGINE = InnoDB;
+CREATE TABLE PackageLicenses (
+	PackageID INTEGER UNSIGNED NOT NULL,
+	LicenseID INTEGER UNSIGNED NOT NULL,
+	PRIMARY KEY (PackageID, LicenseID),
+	FOREIGN KEY (PackageID) REFERENCES Packages(ID) ON DELETE CASCADE,
+	FOREIGN KEY (LicenseID) REFERENCES Licenses(ID) ON DELETE CASCADE
+) ENGINE = InnoDB;
+----
+
+19. Convert existing licenses to the new storage format:
+
+----
+INSERT INTO Licenses (Name) SELECT DISTINCT License FROM Packages;
+INSERT INTO PackageLicenses (PackageID, LicenseID)
+	SELECT Packages.ID, Licenses.ID FROM Packages
+	INNER JOIN Licenses ON Licenses.Name = Packages.License;
+----
+
+20. Delete the license column from the Packages table:
+
+----
+ALTER TABLE Packages DROP COLUMN License;
+----
+
 From 2.2.0 to 2.3.0
 -------------------