创建表名 t_student 主键为 id
CREATE TABLE t_student (id integer PRIMARY KEY, name text,age integer,score real);
如果不存在就创建
CREATE TABLE IF NOT EXISTS t_student (id integer PRIMARY KEY, name text,age integer,score real);
主键自动长
CREATE TABLE IF NOT EXISTS t_student (id integer PRIMARY KEY AUTOINCREMENT, name text,age integer,score real);
增加数据
INSERT INTO t_student (name,age,score) VALUES ('jams',10,10);
更新 全部设了99
UPDATE t_student SET score = 99;
删除内容 某
DELETE FROM t_student WHERE id = 2;
删除内容表内全部
DELETE FROM t_student;
删除整表
DROP TABLE t_student;
查找
SELECT * FROM t_student WHERE age > 50;
查找 总数
SELECT count(name) FROM t_student WHERE age > 50;
模糊查询 %5%
SELECT name , phone FROM t_student WHERE phone LIKE '%%%@%%'
/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;
/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;
/分页/ 从第几个后 开始 取多少个 0 5 5 5 10 5
SELECT * FROM t_student ORDER BY id ASC LIMIT 30, 10;
/简单约束/ 主键PRIMARY KEY 自动增长AUTOINCREMENT
不会空 NOT NULL 默认DEFAULT 1
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);
------------------------oc创建数据库-------------------------------
添加动态库
import "ViewController.h"
import <sqlite3.h>
添加动态库
import "ViewController.h"
import <sqlite3.h>
@interface ViewController ()
{
sqlite3 *_db;
}
@end
@implementation ViewController
-
(void)viewDidLoad {
[super viewDidLoad];
//1. 创建了一个数据库的 文件//1> 数据库文件路径 2>数据库的句柄 3>
NSString *path = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
NSString *dbPath = [path stringByAppendingPathComponent:@"test.sqlite"];
NSLog(@"%@",dbPath);
//打开数据库文件 如果没有就创建一个
int result = sqlite3_open(dbPath.UTF8String, &_db);if (result == SQLITE_OK) {
NSLog(@"创建数据库成功!");
//2. 创建表 指定字段
NSString *sql = [NSString stringWithFormat:@"CREATE TABLE IF NOT EXISTS t_student (id INTEGER PRIMARY KEY AUTOINCREMENT , name TEXT , score REAL)"];
char *eror = nil;
int tableOk = sqlite3_exec(_db, sql.UTF8String, NULL, NULL,&eror);
if (tableOk == SQLITE_OK) {
NSLog(@"创建表成功!");
}else{
NSLog(@"创建表失败!");
}
//3. 填充数据
//crud
}else{
NSLog(@"创建数据库失败!");
}
}
-
(IBAction)adddb {
//2. 增加 数据 100条for (int i = 0; i < 100; i++) {
NSString *sql = [NSString stringWithFormat:@"INSERT INTO t_student (name , score) VALUES('JACK-%d',%f)",i,arc4random_uniform(1000)/10.0];
char *eror = nil;
int tableOk = sqlite3_exec(_db, sql.UTF8String, NULL, NULL,&eror);if (tableOk == SQLITE_OK) { NSLog(@"添加数据成功!"); }else{ NSLog(@"添加数据失败!"); }}
}
-
(IBAction)deletedb {
NSString *sql = [NSString stringWithFormat:@"DELETE FROM t_student WHERE score < 20"];
char *eror = nil;
int tableOk = sqlite3_exec(_db, sql.UTF8String, NULL, NULL,&eror);if (tableOk == SQLITE_OK) {
NSLog(@"删除数据成功!");
}else{
NSLog(@"删除数据失败!");
}
} -
(IBAction)updatedb {
NSString *sql = [NSString stringWithFormat:@"UPDATE t_student SET name = 'kobe' WHERE id < 50"];
char *eror = nil;
int tableOk = sqlite3_exec(_db, sql.UTF8String, NULL, NULL,&eror);if (tableOk == SQLITE_OK) {
NSLog(@"更新数据成功!");
}else{
NSLog(@"更新数据失败!");
}
}
- (IBAction)selectdb {
//参数1> 数据库的指针 2>sql语句 3> 负责接收处理结果
sqlite3_stmt *stmt = nil;
NSString *sql = [NSString stringWithFormat:@"SELECT id,name , score FROM t_student WHERE score > 60"];
int result = sqlite3_prepare_v2(_db, sql.UTF8String, -1, &stmt, NULL);
if (result == SQLITE_OK) {
while(sqlite3_step(stmt) == SQLITE_ROW){
int s_id = sqlite3_column_int(stmt,0);
unsigned char *name = (unsigned char *) sqlite3_column_text(stmt,1);
double score = sqlite3_column_double(stmt,2);
NSLog(@"%d - %@ - %f",s_id,[NSString stringWithUTF8String:(const char *)name],score);
}
}
}
@end
