Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ====== SQL design tool ====== * Entity-Relationship diagram maker: * yed: http://www.yworks.com/en/index.html * yED graph editor: http://www.yworks.com/en/products_yed_about.html * MySQL workbench: http://www.mysql.com/products/workbench/ * sqlite tool in firefox * https://addons.mozilla.org/en-US/firefox/addon/sqlite-manager/ * sqlite desktop tool * DB Browser for SQLite: https://sqlitebrowser.org/ ====== database algebra ====== * symbols: http://en.wikipedia.org/wiki/Relational_algebra ====== Field Type ====== * int: integer; length: how many digits. * AI: auto incremental * varchar: characters; length: how many characters to enter (128) * date: enter it yourself or current timestamp * float(n,d): n for length, and d for decimal point from right Prime vs Unique: * Prime for data linking * Unique for indexing and searching * BLOB type: a binary data type, "binary large object" * read and write photo file in DB: http://www.mysqltutorial.org/python-mysql-blob/ devwiki/sql.txt Last modified: 2021/08/28 07:47by ying