sqlite3是一个可以放在工程中的本地数据库，其大小几百k，通过对c语言的封装，sqlite3有自己的语句对数据库中的数据进行处理，一般应用在对数据进行复杂处理的app中。
/*简单约束*/
CREATE TABLE IF NOT EXISTS t_student(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER);
CREATE TABLE IF NOT EXISTS t_student(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT NOT NULL, age INTEGER NOT NULL);
CREATE TABLE IF NOT EXISTS t_student(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT UNIQUE, age INTEGER);
CREATE TABLE IF NOT EXISTS t_student(id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER DEFAULT 1);
/*分页*/
SELECT * FROM t_student ORDER BY id ASC LIMIT 30, 10;
/*排序*/
SELECT * FROM t_student WHERE score > 50 ORDER BY age DESC;
SELECT * FROM t_student WHERE score < 50 ORDER BY age ASC , score DESC;
/*计量*/
SELECT COUNT(*) FROM t_student WHERE age > 50;
/*别名*/
SELECT name as myName, age as myAge, score as myScore FROM t_student;
SELECT name myName, age myAge, score myScore FROM t_student;
SELECT s.name myName, s.age myAge, s.score myScore FROM t_student s WHERE s.age > 50;
/*查询*/
SELECT name, age, score FROM t_student;
SELECT * FROM t_student;
/*修改指定数据*/
UPDATE t_student SET name = 'MM' WHERE age = 10;
UPDATE t_student SET name = 'WW' WHERE age is 7;
UPDATE t_student SET name = 'XXOO' WHERE age < 20;
UPDATE t_student SET name = 'NNMM' WHERE age < 50 and score > 10;
/*删除数据*/
DELETE FROM t_student;
/*更新数据*/
UPDATE t_student SET name = 'LNJ';
/*插入数据*/
INSERT INTO t_student(age, score, name) VALUES ('28', 100, 'jonathan');
INSERT INTO t_student(name, age) VALUES ('lee', '28');
INSERT INTO t_student(score) VALUES (100);
/*插入数据*/
INSERT INTO t_student(name, age, score) VALUES ('lee', '28', 100);
/*添加主键*/
CREATE TABLE IF NOT EXISTS t_student (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER, score REAL);
/*添加主键*/
CREATE TABLE IF NOT EXISTS t_student (id INTEGER, name TEXT, age INTEGER, score REAL, PRIMARY KEY(id));
/*删除表*/
DROP TABLE IF EXISTS t_student;
/*创建表*/
CREATE TABLE IF NOT EXISTS t_student(id INTEGER , name TEXT, age , score REAL);