iOS Sqlite3 Demo 及 FMDB Demo

　　本文是主要实现了三个函数：

• 　　testSQLite3 是测试系统自带的sqlite3的demo
• 　　testFMDB是测试FMDB存取简单的数据类型的 的demo
• 　　testFMDB2是将任意对象作为一个整体存入到FMDB的Demo

　　首先先定义了一个Person类，实现了<NSCoding>协议，对Person对象进行字段存取和整体存取

 //Person.h
 #import <Foundation/Foundation.h>

 @interface Person : NSObject<NSCoding>
 @property (nonatomic ,assign)int id;
 @property (nonatomic ,copy) NSString *name;
 @property (nonatomic ,assign)int age;
 @end

 //Person.m
 #import "Person.h"

 @implementation Person
 -(NSString *)description{
     return [NSString stringWithFormat:@"id:%d--name:%@--age:%d",self.id,self.name,self.age];
 }
 -(instancetype)initWithCoder:(NSCoder *)decoder{
     if (self = [super init]) {
         self.id = [decoder decodeIntForKey:@"id"];
         self.name = [decoder decodeObjectForKey:@"name"];
         self.age = [decoder decodeIntForKey:@"age"];
     }
     return self;
 }
 -(void)encodeWithCoder:(NSCoder *)encoder{
     [encoder encodeInt:self.id
                 forKey:@"id"];
     [encoder encodeObject:self.name forKey:@"name"];
     [encoder encodeInt:self.age forKey:@"age"];
 }
 @end

Person

 -(void)testSQLite3{
     //1. 打开(建立)数据库
     NSString *cacheDir = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
     NSString *filename = [cacheDir stringByAppendingPathComponent:@"test.sqlite"];
     sqlite3 * db = nil;

     //0表示成功，1表示失败
     sqlite3_open(filename.UTF8String, &db);
     if (!db) {
         NSLog(@"数据库打开失败，建立失败");
         return;
     }
     char *errmsg = nil;
     //2.一般用来执行无返回结果的sql 命令,（可以执行任何SQL语句）
     //创建数据库
     char * createTableSql = "create table  t_person(id integer primary key,name text not null unique,age integer);";
     int rs = sqlite3_exec(db, createTableSql, NULL, NULL, &errmsg);

     if (errmsg) {
         NSLog(@"%s--errorCode:%d",errmsg,rs);
     }
     //3.插入数据
     for(NSUInteger i = ;i < ;i ++){
         NSString *insertSql = [NSString stringWithFormat:@"insert into t_person(name,age) values('小hong%lu',%d);",(unsigned long)i,arc4random()%+];
         char *errmsg = nil;
         sqlite3_exec(db, insertSql.UTF8String, NULL, NULL, &errmsg);
         if (errmsg) {
             NSLog(@"insert error:%s",errmsg);
         }
     }
     //4.查询数据 尽量使用const char * 不要用NSString ,容易出错
     const char* selectSql =  "select * from t_person where name like '小明%' and age < 20 order by age desc limit 1,10";
     sqlite3_stmt * stmt = nil;
     sqlite3_prepare(db, selectSql, (int)strlen(selectSql), &stmt, NULL);
     if (stmt) {
         while (sqlite3_step(stmt) == SQLITE_ROW) {
             Person *person = [[Person alloc]init];
             person.id =  sqlite3_column_int(stmt, );
             person.name = [NSString stringWithUTF8String:(char *)sqlite3_column_text(stmt, )];
             person.age = sqlite3_column_int(stmt, );
             NSLog(@"%@",person);
         }
     }

testSQLite3

 -(void)testFMDB{
     NSString *cacheDir = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
     NSString *filename = [cacheDir stringByAppendingPathComponent:@"new.sqlite"];
     //1.建立数据库对象，一个数据库对应一个数据库对象
     FMDatabase * db = [FMDatabase databaseWithPath:filename];
     //2.打开数据库
     if (![db open]) {
         NSLog(@"数据库连接或者创建失败");
         return;
     }
     //3. 建表
     NSString *createSql = @"create table  if not exists t_person(id integer primary key,name text not null unique,age integer);";
     if (![db executeUpdate:createSql]) {
         NSLog(@"error:%@",[db lastErrorMessage]);
     }
     //4.插入数据
     for (int i = ; i< ; i++) {
         //fmdb 最好自己把你的sql字符串用NSString写出来
         NSString * insertSql = [NSString stringWithFormat:@"insert into t_person(name,age) values('xiaoming%d',%d)",i,arc4random()%];
         if (![db executeUpdate:insertSql]) {
             NSLog(@"error:%@",[db lastErrorMessage]);
         }
     }
     //5.修改数据
     NSString *updateStr = [NSString stringWithFormat:@"update t_person set age = 1000"];
     if (![db executeUpdate:updateStr]) {
         NSLog(@"error:%@",[db lastErrorMessage]);
     }
     //6. 删除数据
     NSString *deleteStr= [NSString stringWithFormat:@"delete from t_person where id =1;"];
     if (![db executeUpdate:deleteStr]) {
         NSLog(@"error:%@",[db lastErrorMessage]);
     }
     //7.查询数据
     NSString *querySql = [NSString stringWithFormat:@"select * from t_person"];
     FMResultSet * set = [db executeQuery:querySql];
     while (set.next) {
         Person *person = [[Person alloc]init];
         person.id = [set intForColumn:@"id"];
         person.name = [set stringForColumn:@"name"];
         person.age = [set intForColumn:@"age"];
         NSLog(@"%@",person);
     }
 }

testFMDB

 //存取任意对象
 -(void)testFMDB2{
     NSString *cacheDir = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
     NSString *filename = [cacheDir stringByAppendingPathComponent:@"Person.sqlite"];
     //1.建立数据库对象，一个数据库对应一个数据库对象
     FMDatabase * db = [FMDatabase databaseWithPath:filename];
     //2.打开数据库
     if (![db open]) {
         NSLog(@"数据库连接或者创建失败");
         return;
     }
     //3. 建表
     NSString *createSql = @"create table  if not exists t_persons(id integer primary key,person blob not null unique,age integer);";
     if (![db executeUpdate:createSql]) {
         NSLog(@"error:%@",[db lastErrorMessage]);
     }
     //4.插入数据
     for (int i = ; i< ; i++) {
         //将对象作为一个整体存入到数据库中
         Person *person = [[Person alloc]init];
         person.name = [NSString stringWithFormat:@"xiaoming%d",i];
         person.age = arc4random()%;
         person.id = arc4random();
         NSData *data = [NSKeyedArchiver archivedDataWithRootObject:person];
         //插入blob 数据一定要使用excuteUpdateWithFormat:， 直接用executeUpdate:会报错的，因为你的数据使用NSLog打印出来会带有<>符号
         if (![db executeUpdateWithFormat:@"insert into t_persons(person,age) values(%@,%d)",data,person.age]) {
             NSLog(@"error:%@",[db lastErrorMessage]);
         }
     }
     //5.修改数据
     NSString *updateStr = [NSString stringWithFormat:@"update t_persons set age = 1000"];
     if (![db executeUpdate:updateStr]) {
         NSLog(@"error:%@",[db lastErrorMessage]);
     }
     //6. 删除数据
     NSString *deleteStr= [NSString stringWithFormat:@"delete from t_persons where id =1;"];
     if (![db executeUpdate:deleteStr]) {
         NSLog(@"error:%@",[db lastErrorMessage]);
     }
     //7.查询数据
     NSString *querySql = [NSString stringWithFormat:@"select * from t_persons "];
     FMResultSet * set = [db executeQuery:querySql];
     while (set.next) {
         NSData *data = [set dataForColumn:@"person"];
 //        NSLog(@"%@",data);
         Person *person = [NSKeyedUnarchiver unarchiveObjectWithData:data];
         person.id = [set intForColumn:@"id"];
         NSLog(@"%@",person);
     }

 }

testFMDB2