Ios开发之sqlite

Sqlite是ios数据存储的一个重要手段，今天我们就一块来看一下，怎样使用sqlite将数据存储到沙盒中去。

第一步：导入一个框架libsqlite3.0.dylib

选中TARGETS在General中的Linked Frameworks and Libraries选项中点击‘＋’添加

第二步：代码部分

1.找到沙盒中的路径

NSArray *path =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  NSString *documentPath = [path objectAtIndex:0];   NSString *dbPath = [documentPath stringByAppendingPathComponent:@"sqlite.db"];

2.创建sqlite对象，并执行打开操作

sqlite3 *db;      //打开数据库  int res = sqlite3_open(dbPath.UTF8String, &db);

3.创建表

NSString *sql = @"create table if not exists 'student' ('id' integer primary key autoincrement,'studentname' varchar)";  int sqlRes = sqlite3_exec(db, sql.UTF8String, NULL, NULL, NULL);   if (sqlRes == SQLITE_OK) {       NSLog(@"create table ok");   }

4.向表中插入数据

//增 NSString *sql1 = @"insert into student (studentname) values ('小帐')";  int sql1Res = sqlite3_exec(db, sql1.UTF8String, NULL, NULL, NULL);  if (sql1Res == SQLITE_OK) {      NSLog(@"insert ok");  }

5.从表中删除数据

NSString *deletesql  = @"delete from student where id = 3";  int deleres = sqlite3_exec(db, deletesql.UTF8String, NULL, NULL, NULL);  if (deleres == SQLITE_OK) {       NSLog(@"delete is ok");  }

6.修改表中的数据

//修改  NSString *updateSql = @"update student set studentname = 'wangling' where id = 4";  int updateres = sqlite3_exec(db, updateSql.UTF8String, NULL, NULL, NULL);  if (updateres == SQLITE_OK) {        NSLog(@"update is ok");  }

7.查询数据

查询数据和，增删改都有所不同，我们需要首先创建sqlite_stmt对象，用来存放我们查询的数据流（二进制），然后使用sqlite3_prepare_v2函数准备,通过sqlite3_bind_添加查询参数最后获取数据，最后关闭sqlite_stmt对象。

//查          sqlite3_stmt *stmt;          NSString *selectSql = @"select * from student where id ＝ ？";            if (sqlite3_prepare_v2(db, selectSql.UTF8String, -1, &stmt, nil) == SQLITE_OK) {              sqlite3_bind_int(stmt, 1, 4);              while (sqlite3_step(stmt) == SQLITE_ROW) {                  int identity = sqlite3_column_int(stmt, 0);                  NSLog(@"%d",identity);                  char * name= (char *)sqlite3_column_text(stmt, 1);                  NSLog(@"%@",[NSString stringWithUTF8String:name]);              }              if (stmt) {                  sqlite3_finalize(stmt);  }

8.关闭数据库sqlite对象

if (db) {          sqlite3_close(db);      }