首先，添加framework：libsqlite3.0.dylib需要在對應文件的頭文件中加入：#import "/usr/include/sqlite3.h" 并在Frameworks中加入所需的庫，否則會報錯：Undefined symbols: "_sqlite3_open", referenced from: 加入庫的方法是：image 選擇sqlite庫：image 選擇完的效果：image 下面是代碼：//sqlite [self openDataBase]; //[self createTable]; //[self insertTable]; [self queryTable]; [self deleteTable]; [self queryTable]; 實現：//open database - (void)openDataBase { NSArray *documentsPaths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask , YES); NSString *databaseFilePath=[[documentsPaths objectAtIndex:0] stringByAppendingPathComponent:@"db.sql"]; if (sqlite3_open([databaseFilePath UTF8String], &database)==SQLITE_OK) { NSLog(@"open sqlite db ok."); } else { NSLog( @"can not open sqlite db " ); //close database sqlite3_close(database); } } //create table - (void)createTable { char *errorMsg; const char *createSql="create table if not exists persons (id integer primary key autoincrement,name text)"; if (sqlite3_exec(database, createSql, NULL, NULL, &errorMsg)==SQLITE_OK) { NSLog(@"create ok."); } else { NSLog( @"can not create table" ); [self ErrorReport:(NSString *)createSql]; } } //insert table - (void)insertTable { char *errorMsg; const char *insertSql="insert into persons (name) values ('田周輝')"; if (sqlite3_exec(database, insertSql, NULL, NULL, &errorMsg)==SQLITE_OK) { NSLog(@"insert ok."); } else { NSLog( @"can not insert it to table" ); [self ErrorReport: (NSString *)insertSql]; } } //error - (void)ErrorReport: (NSString *)item { char *errorMsg; if (sqlite3_exec(database, (const char *)item, NULL, NULL, &errorMsg)==SQLITE_OK) { NSLog(@"%@ ok.",item); } else { NSLog(@"error: %s",errorMsg); sqlite3_free(errorMsg); } } //query table - (void)queryTable { const char *selectSql="select id,name from persons"; sqlite3_stmt *statement; if (sqlite3_prepare_v2(database, selectSql, -1, &statement, nil)==SQLITE_OK) { NSLog(@"select ok."); while (sqlite3_step(statement)==SQLITE_ROW)//SQLITE_OK SQLITE_ROW { int _id=sqlite3_column_int(statement, 0); NSString *name=[[NSString alloc] initWithCString:(char *)sqlite3_column_text(statement, 1) encoding:NSUTF8StringEncoding]; NSLog(@"row>>id %i, name>> %@",_id,name); } } else { //error [self ErrorReport: (NSString *)selectSql]; } sqlite3_finalize(statement); } //delete table - (void)deleteTable { char *errorMsg; [self openDataBase]; const char *sql = "DELETE FROM persons where id=24"; if (sqlite3_exec(database, sql, NULL, NULL, &errorMsg)==SQLITE_OK) { NSLog(@"delete ok."); } else { NSLog( @"can not delete it" ); [self ErrorReport: (NSString *)sql]; } } 命令行：sqlite3 database //創建數據庫 crate table tableFile(id smallint, file_name varchar(256), up_state smallint, file_size smallint); //創建一個表格 insert into tableFile values(1, "200110101.rcu", 100, 4500); //插入數據 5 如何訪問SQLite3數據庫 sqlite3_open //打開數據庫 sqlite3_prepare //將UTF－8格式的SQL語句轉換為指向已備語句的指針 sqlite3_column_string //返回某一行的字符串 sqlite3_finalize //刪除一條已備語句 sqlite3_close //關閉數據庫 6 source code - (id)lookupSingularSQL:(NSString *)sql forType:(NSString *)rettype { sqlite3_stmt *statement; id result; if (statement = [self prepare:sql]) { if (sqlite3_step(statement) == SQLITE_ROW) { if ([rettype compare:@"text"] == NSOrderedSame) { char temp_buf[256]; memset(temp_buf, 0, 256); sprintf(temp_buf, "%s %s %s %s", (char *)sqlite3_column_text(statement,0), (char *)sqlite3_column_text(statement,1), (char *)sqlite3_column_text(statement,2), (char *)sqlite3_column_text(statement,3) ); result = [NSString stringWithUTF8String:temp_buf]; //result = [NSString stringWithUTF8String:(char *)sqlite3_column_text(statement,0)]; } else if ([rettype compare:@"integer"] == NSOrderedSame) { result = (id)sqlite3_column_int(statement,0); } } } sqlite3_finalize(statement); return result; } 應該有個成員變量，比如我的代碼：@interface DetailViewController : UIViewController { UIPopoverController *popoverController; UIToolbar *toolbar; id detailItem; UILabel *detailDescriptionLabel; sqlite3 *database; 打開數據庫SQLite數據庫是文件數據庫，是保存在文件系統中的。因此需要知道文件保存到哪里，可參見iOS中對文件的操作。比如本文保存到Documents目錄下。代碼：NSArray *documentsPaths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask , YES); NSString *databaseFilePath=[[documentsPaths objectAtIndex:0] stringByAppendingPathComponent:@"mydb"]; if (sqlite3_open([databaseFilePath UTF8String], &database)==SQLITE_OK) { NSLog(@"open sqlite db ok."); } 通過ssh查看Documents目錄，發現mydb文件已經創建。sqlite的策略是如果有該文件就打開，如果沒有就創建文件，也就是創建數據庫。這里要注意，使用的是C語法，sqlite3_open傳入的是database的地址。關閉數據庫數據庫使用完畢后，要關閉，比如退出應用的時候：- (void)viewDidUnload { // Release any retained subviews of the main view. // e.g. self.myOutlet = nil; sqlite3_close(database); self.popoverController = nil; } 建表語句數據庫打開以后，如果沒有表，建表：char *errorMsg; const char *createSql="create table if not exists persons (id integer primary key autoincrement,name text)"; if (sqlite3_exec(database, createSql, NULL, NULL, &errorMsg)==SQLITE_OK) { NSLog(@"create ok."); } 這里要特別注意errorMsg傳的是地址，因為該函數要通過地址引用來寫報錯字符信息。向表中插入記錄和建表語句類似：const char *insertSql="insert into persons (name) values(‘張三’)"; if (sqlite3_exec(database, insertSql, NULL, NULL, &errorMsg)==SQLITE_OK) { NSLog(@"insert ok."); } 錯誤信息的處理如果在多個地方使用errorMsg，那么每次使用完畢要清空一下字串，比如這樣：if (sqlite3_exec(database, createSql, NULL, NULL, &errorMsg)==SQLITE_OK) { NSLog(@"create ok."); }else { NSLog(@"error: %s",errorMsg); sqlite3_free(errorMsg); } 查詢結果集結果集的查詢，需要用到statement：const char *selectSql="select id,name from persons"; sqlite3_stmt *statement; if (sqlite3_prepare_v2(database, selectSql, -1, &statement, nil)==SQLITE_OK) { NSLog(@"select ok."); } while (sqlite3_step(statement)==SQLITE_ROW) { int _id=sqlite3_column_int(statement, 0); char *name=(char *)sqlite3_column_text(statement, 1); NSLog(@"row>>id %i, name %s",_id,name); } sqlite3_finalize(statement); 不過這里有個問題，看看打印的日志：image 亂碼。因為直接用的char類型來做的。解決辦法是，用nsstring替代char：while (sqlite3_step(statement)==SQLITE_ROW) { int _id=sqlite3_column_int(statement, 0); NSString *name=[[NSString alloc] initWithCString:(char *)sqlite3_column_text(statement, 1) encoding:NSUTF8StringEncoding]; NSLog(@"row>>id %i, name %@",_id,name); } char生成nsstring的時候做一次顯式的編碼。問題解決：image 這說明：寫入數據庫，用char的方式沒有問題，寫入數據庫的編碼是對的;從庫中取出，可能默認使用ascii解碼，造成顯示亂碼。使用sqlite c api，要經常參考官方函數文檔：http://www.sqlite.org/c3ref/funclist.html

　　

轉載于:https://www.cnblogs.com/deng37s/p/4599922.html

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