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iOS 原生sqlite3的使用方法

2020-07-26 02:35:04
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本文介紹了iOS 原生sqlite3的使用方法,分享給大家,具體如下:

SQLite?

  1. SQLit是一個(gè)開(kāi)源、輕型嵌入式關(guān)系數(shù)據(jù)庫(kù),誕生于2000年5月
  2. 占用資源非常的低,在嵌入式設(shè)備中,可能只需要幾百K的內(nèi)存就夠了
  3. 能夠支持Windows/Linux/Unix等等主流的操作系統(tǒng)
  4. 比起Mysql、PostgreSQL這兩款開(kāi)源的世界著名數(shù)據(jù)庫(kù)管理系統(tǒng)來(lái)講,它的處理速度比他們都快

 SQL語(yǔ)句常用操作

增、刪、改、查,CRUD,Create[新建], Retrieve[檢索], Update[更新], Delete[刪除]。

SQL語(yǔ)法寫法特點(diǎn)

1、不區(qū)分大小寫(CREATE = create)
2、每條語(yǔ)句以分號(hào)(;)結(jié)尾
3、關(guān)鍵字建議大寫

SQL語(yǔ)句常用關(guān)鍵字

select、insert、update、delete、from、create、where、desc、order、by、group、table、alter、view、index等

  1. 數(shù)據(jù)定義語(yǔ)句(DDL):包括create和drop等操作,在數(shù)據(jù)庫(kù)中創(chuàng)建新表或刪除表(create table或 drop table)
  2. 數(shù)據(jù)操作語(yǔ)句(DML):包括insert、update、delete等操作,分別用于添加、修改、刪除表中的數(shù)據(jù)
  3. 數(shù)據(jù)查詢語(yǔ)句(DQL):可以用于查詢獲得表中的數(shù)據(jù),關(guān)鍵字select是DQL(也是所有SQL)用得最多的操作,其他DQL常用的關(guān)鍵字有where,order by,group by和having
// ViewController.m// sqlite3//// Created by 周玉 on 2017/12/13.// Copyright © 2017年 guidekj. All rights reserved.//#import "ViewController.h"#import <sqlite3.h>#define KUIScreenWidth [UIScreen mainScreen].bounds.size.width#define KUIScreenHeight [UIScreen mainScreen].bounds.size.height#define FILE_NAME @"saas.sqlite"static sqlite3 *db = nil;@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {  [super viewDidLoad];  self.title = @"sqlite3";  //DDB//  [self openDB];//  [self closeDB];  //DDL//  [self createTable];//  [self dropTable];  //DML//  [self insertData];//  [self updateData];//  [self deleteData];  //DQL  [self queryData];}#pragma mark 查詢- (void)queryData{  sqlite3 *newDB = [self openDB];  sqlite3_stmt *statement = nil;  NSString *sqlStr = @"SELECT * FROM SAAS_PERSON";  int result = sqlite3_prepare_v2(newDB, sqlStr.UTF8String, -1, &statement, NULL);  if (result == SQLITE_OK) {    //遍歷查詢結(jié)果    if (!(sqlite3_step(statement) == SQLITE_DONE)) {      while (sqlite3_step(statement) == SQLITE_ROW) {        int ID = sqlite3_column_int(statement, 0);        const unsigned char *name = sqlite3_column_text(statement, 1);        const unsigned char *sex = sqlite3_column_text(statement, 2);        int age = sqlite3_column_int(statement, 3);        const unsigned char *description = sqlite3_column_text(statement, 4);        NSLog(@"ID = %d , name = %@ , sex = %@ , age = %d , description = %@",ID,[NSString stringWithUTF8String:(const char *)name],[NSString stringWithUTF8String:(const char *)sex],age,[NSString stringWithUTF8String:(const char *)description]);      }    } else {      NSLog(@"查詢語(yǔ)句完成");    }  } else {    NSLog(@"查詢語(yǔ)句不合法");  }  sqlite3_finalize(statement);  [self closeDB];}#pragma mark 刪除數(shù)據(jù)記錄- (void)deleteData{  sqlite3 *newDB = [self openDB];  sqlite3_stmt *statement = nil;  NSString *sqlStr = @"DELETE FROM SAAS_PERSON WHERE NAME = '王鵬飛'";  int result = sqlite3_prepare_v2(newDB, sqlStr.UTF8String, -1, &statement, NULL);  if (result == SQLITE_OK) {    if (sqlite3_step(statement) == SQLITE_DONE) {      NSLog(@"刪除操作完成");    }  } else {    NSLog(@"刪除操作不合法");  }  sqlite3_finalize(statement);  [self closeDB];}#pragma mark 更新數(shù)據(jù)記錄- (void)updateData{  sqlite3 *newDB = [self openDB];  sqlite3_stmt *statement = nil;  NSString *sqlStr = @"UPDATE SAAS_PERSON SET DESCRIPTION = '喜歡運(yùn)動(dòng),旅游' WHERE NAME = '周玉'";  int result = sqlite3_prepare_v2(newDB, sqlStr.UTF8String, -1, &statement, NULL);  if (result == SQLITE_OK) {    if (sqlite3_step(statement) == SQLITE_DONE) {      NSLog(@"更新信息完成");    }  } else {    //[logging] no such column: DESCRIPT (KEY拼寫錯(cuò)誤) --- 更新信息不合法    NSLog(@"更新信息不合法");  }  sqlite3_finalize(statement);  [self closeDB];}#pragma mark 新增數(shù)據(jù)記錄- (void)insertData{  sqlite3 *newDB = [self openDB];  sqlite3_stmt *statement = nil;//  NSString *sqlStr = @"INSERT INTO SAAS_PERSON (NAME , SEX , AGE , DESCRIPTION) VALUES('周玉','男',28,'開(kāi)朗樂(lè)觀')";//  NSString *sqlStr = @"INSERT INTO SAAS_PERSON (NAME , SEX , AGE , DESCRIPTION) VALUES('王鵬飛','女',27,'開(kāi)朗樂(lè)觀')";//  NSString *sqlStr = @"INSERT INTO SAAS_PERSON (NAME , SEX , AGE , DESCRIPTION) VALUES('李梅','女',20,'年輕可愛(ài)��')";  NSString *sqlStr = @"INSERT INTO SAAS_PERSON (NAME , SEX , AGE , DESCRIPTION) VALUES('sumit','男',15,'小朋友的年紀(jì)')";  //檢驗(yàn)合法性  int result = sqlite3_prepare_v2(newDB, sqlStr.UTF8String, -1, &statement, NULL);  if (result == SQLITE_OK) {    //判斷語(yǔ)句執(zhí)行完畢    if (sqlite3_step(statement) == SQLITE_DONE) {      NSLog(@"插入的信息完成");    }  } else {    NSLog(@"插入的信息不合法");  }  sqlite3_finalize(statement);  [self closeDB];}#pragma mark 創(chuàng)建表- (void)createTable{  sqlite3 *newDB = [self openDB];  //  char *sql = "CREATE TABLE IF NOT EXISTS t_person (ID INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, NAME TEXT , SEX TEXT,AGE INTEGER,DESCRIPTION TEXT);";  NSString *sqlStr = @"CREATE TABLE IF NOT EXISTS SAAS_PERSON (ID INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, NAME TEXT , SEX TEXT,AGE INTEGER,DESCRIPTION TEXT);";  char *error = NULL;  int result = sqlite3_exec(newDB, sqlStr.UTF8String, NULL, NULL, &error);  if (result == SQLITE_OK) {    NSLog(@"創(chuàng)建表成功");  } else {    NSLog(@"創(chuàng)建表失敗 = %s",error);  }  [self closeDB];}#pragma mark 刪除表- (void)dropTable{  sqlite3 *newDB = [self openDB];  NSString *sqlStr = @"DROP TABLE t_person";  char *error = NULL;  int result = sqlite3_exec(newDB, sqlStr.UTF8String, NULL, NULL, &error);  if (result == SQLITE_OK) {    NSLog(@"刪除表成功");  } else {    NSLog(@"刪除表失敗 = %s",error);  }  [self closeDB];}#pragma mark 打開(kāi)或者創(chuàng)建數(shù)據(jù)庫(kù)- (sqlite3 *)openDB {  if (!db) {    //1.獲取document文件夾的路徑    //參數(shù)1:文件夾的名字 參數(shù)2:查找域 參數(shù)3:是否使用絕對(duì)路徑    NSString *documentPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];    //獲取數(shù)據(jù)庫(kù)文件的路徑    NSString *dbPath = [documentPath stringByAppendingPathComponent:@"saas.sqlite"];    NSLog(@"%@",dbPath);    //判斷document中是否有sqlite文件    int result = sqlite3_open([dbPath UTF8String], &db);    if (result == SQLITE_OK) {      NSLog(@"打開(kāi)數(shù)據(jù)庫(kù)");    }else{      [self closeDB];      NSLog(@"打開(kāi)數(shù)據(jù)庫(kù)失敗");    }  }  return db;}#pragma mark 關(guān)閉數(shù)據(jù)庫(kù)- (void)closeDB{  int result = sqlite3_close(db);  if (result == SQLITE_OK) {    NSLog(@"數(shù)據(jù)庫(kù)關(guān)閉成功");    db = nil;  } else {    NSLog(@"數(shù)據(jù)庫(kù)關(guān)閉失敗");  }}@end

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