iOS basic use of Fmdb

A brief introduction to the Fmdb,fmdb is the SQLite database framework of the iOS platform, which encapsulates SQLite's C language API in OC mode. Easy to use, save a lot of redundant C language code, compared to Apple's own core data framework, more lightweight and flexible, provide multi-threaded secure database operation method, effectively prevent data confusion.

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GitHub Address

Https://github.com/ccgus/fmdb

Specific use:

1. Import the Fmdb into your project and add the LIBSQLITE3.TBD (Xcode7 later version).

2.

#import <Foundation/Foundation.h> @interface databasemanager:nsobject//Write a single case + (instancetype) sharedfmdatabase;

#import "DataBaseManager.h" #import "FMDB.h" @interface Databasemanager () @property (nonatomic,strong) fmdatabase * db;@    End@implementation databasemanager+ (instancetype) sharedfmdatabase{static databasemanager*manager=nil;    Static dispatch_once_t Oncetoken;    Dispatch_once (&oncetoken, ^{Manager=[[databasemanager Alloc]init];    }); Return manager;}    -(instancetype) init{self = [super init];         if (self) {nsstring*doc=nssearchpathfordirectoriesindomains (nsdocumentdirectory, Nsuserdomainmask, YES) [0];//Get the database        Nsstring*filename=[doc stringbyappendingpathcomponent:@ "Students.sqlite"];                A database file is created automatically when a database file does not exist.        Determine if the database exists if (!self.db) {//does not exist create self.db=[fmdatabase databasewithpath:filename];        }//Set cache for database, improve query efficiency [self.db Setshouldcachestatements:yes];        BOOL open=[self.db open];//Test whether the database is open successfully if (open) {NSLog (@ "Database open successfully");        }else{NSLog (@ "Database open failed"); }        Open the database if ([self.db Open]) {if (![                         Self.db tableexists:@ "T_student"]) {//CREATE TABLE BOOL result=[self.db executeupdate:            @ "CREATE TABLES t_student (id INTEGER PRIMARY KEY autoincreament, Name text, age text)"];            The dictionary is converted to NSData, and the SQL is saved with the BLOB type if (result) {NSLog (@ "Success CREATE TABLE");            }else{NSLog (@ "Failure to create a table");        }} NSLog (@ "already has a table and does not need to be added again");            }//close the database [self.db close]; } return self;}

Basic operation of the data:

Add data [self.db open];    [Self.db executeupdate:@ "INSERT into T_student (name,age) VALUES (?,?)" @ "xiaoming" @ "123"];    [Self.db Close];

　　

querying data [self.db open];    Fmresultset*resultset=[self.db executequery:@ "SELECT * from T_student"];    while ([ResultSet next]) {        int id = [ResultSet intforcolumn:@ "id"];        NSString *name = [resultSet stringforcolumn:@ "name"];        nsstring* age = [ResultSet stringforcolumn:@ ' age '];        NSLog (@ "%d%@%@", ID, name, age);    }    [Self.db Close];

　　

　　

iOS basic use of Fmdb