时间:2021-07-01 10:21:17 帮助过:37人阅读
howtouseSQLite3usingtheconsole.SQLiteisanembeddedrelationaldatabasethatdoesn’trequireadedicateddatabasemanagementsystem.Thedatabaseispartofyourcodeandnotanoutsideresource.ThereasonforcreatingSQLitewastoprovideaselfcontaineddatabasethatwase
how to use SQLite3 using the console. SQLite is an embedded relational database that doesn’t require a dedicated database management system. The database is part of your code and not an outside resource. The reason for creating SQLite was to provide a self contained database that was easy to use, could travel with the program using it and run on any machine with no other required software. SQLitesqlite3 test.db // open sqlite and provide a database name // Creates a table in the database // Primary Key automatically generates values that start at 1 and increase by 1 // name is a text field that will hold employee names create table employees (id integer primary key, name text); // Insert some employees insert into employees (id, name) values(1, 'Max Eisenhardt'); insert into employees (name) values('Pietro Maximoff'); insert into employees (name) values('Wanda Maximoff'); insert into employees (name) values('Mortimer Toynbee'); insert into employees (name) values('Jason Wyngarde'); // In column mode, each record is shown on a separate line with the data aligned in columns // headers on shows the column names, if off they wouldn't show .mode column .headers on select * from employees; // Show all employees // Changes the width of the columns .width 15 20 .exit // Closes the database sqlite3 test.db // Reopen database .tables // Displays the tables // Displays every value on its own line .mode line select * from employees; // Shows the statements used to create the database. You could also provide a table name to see how that single table was made .schema OR .schema employees // You can get a more detailed database view .mode column .headers on select type, name, tbl_name, sql from sqlite_master order by type; // Used to show the current settings .show // Set NULL to 'NULL' .nullvalue 'NULL' .show // Change the prompt for SQLite .prompt 'sqlite3> ' .show // Used to export database into SQL format on the screen .dump // Used to output to a file .output ./Documents/sqlite3Files/employees.sql .dump .output stdout // Restores output to the screen // You don't delete a database with any command. You have to delete the file itself // You can delete a table however drop table employees; // You can import the table then with .read ./Documents/sqlite3Files/employees.sql // .mode is used to change the formatting of the output // OPTIONS FOR MODE : column, csv // html: html table // insert: insert commands used // list: List without commas // tabs: Tab separated list // How to output a CSV list to a file .mode csv // You could define the output should be csv .separator , // OR define the separator for the columns .output ./Documents/sqlite3Files/employees.csv .separator , select * from employees; .output stdout // Output html table .mode html select * from employees; .output stdout // line outputs column name and value .mode line select * from employees; .output stdout // Items with double quotes .mode tcl select * from employees; .output stdout