Ios開發之sqlite

Sqlite是ios數據存儲的一個重要手段，今天我們就一塊來看一下，怎樣使用sqlite將數據存儲到沙盒中去。

第一步：導入一個框架libsqlite3.0.dylib

選中TARGETS在General中的Linked Frameworks and Libraries選項中點擊‘＋’添加

第二步：代碼部分

1.找到沙盒中的路徑

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

2.創建sqlite對象，并執行打開操作

sqlite3 *db;
    //打開數據庫
int res = sqlite3_open(dbPath.UTF8String, &db);

3.創建表

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.向表中插入數據

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

5.從表中刪除數據

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.修改表中的數據

//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.查詢數據

查詢數據和，增刪改都有所不同，我們需要首先創建sqlite_stmt對象，用來存放我們查詢的數據流（二進制），然后使用sqlite3_prepare_v2函數準備,通過sqlite3_bind_添加查詢參數最后獲取數據，最后關閉sqlite_stmt對象。

//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.關閉數據庫sqlite對象

if (db) {
        sqlite3_close(db);
    }