SQLite Simple to use

viewcontroller.m//sqlitedemo////Created by Lam_tt on 15-4-11.//Copyright (c) 2015 Lam_tt. All rights reserved.//#import "ViewController.h" #import <sqlite3.h> @interface Viewcontroller () {sqlite3 *_db;}    @end @implementation viewcontroller-(void) viewdidload {[Super viewdidload];    [Self opensqlite];    [Self Initbutton];    }-(void) Initbutton {nsarray *array = [Nsarray alloc]initwithobjects:@ "Add", @ "delete", @ "Change", @ "check", nil];        for (int i = 0; i < 4; i + +) {UIButton *button = [[UIButton alloc]init];        Button.bounds = CGRectMake (0, 0, 150, 30);        Button.tag = ten + i;        [Button settitle:array[i] forstate:uicontrolstatenormal];        Button.backgroundcolor = [Uicolor Graycolor];        [Button addtarget:self action: @selector (buttonpressed:) forcontrolevents:uicontroleventtouchupinside];        Button.center = Cgpointmake (Cgrectgetwidth (self.view.bounds)/2, + i * 50);    [Self.view Addsubview:button]; }} #pragma mark-button click Event-(VOID) buttonpressed: (UIButton *) Sender {Nsinteger index = sender.tag-10;            Switch (index) {case 0: [Self initinsertdata];                    Break            Case 1: [Self initdelete];        Break            Case 2: [Self initupdata];        Break            Case 3: [Self initselect];    Break    }} #pragma mark-create Database-(void) Opensqlite {//Sqlite3 *db;    Path NSString *string = [NSString stringwithformat:@ "%@/documents", Nshomedirectory ()];    NSString *filename = [string stringbyappendingstring:@ "/students.sqlite"];        oc-c const char *cfilename = filename.utf8string;        Open the database without automatically creating an int result = Sqlite3_open (cFileName, &_db);    if (result = = Sqlite_ok) {NSLog (@ "Successfully open database");    }else {NSLog (@ "Failed to open database"); }//Available Sqlitemanger view #pragma mark-Create table const char *sql= "CREATE table IF not EXISTS t_students (ID integer P Rimary KEY autoincrement,name Text not NULL,age integer not NULL); ";        char *errmsg = NULL; Parameters: The first parameter is the database handle (DB), the second parameter is the SQL statement, the third parameter is the callback parameter, is a pointer to the function, if the callback front of the * change to ^ is a block code snippet, the fourth parameter can write null,    The fifth parameter is an error message and is used for code debugging.        result = Sqlite3_exec (_db, SQL, NULL, NULL, &AMP;ERRMSG);    if (result = = Sqlite_ok) {NSLog (@ "CREATE table succeeded");    }else {printf ("Failed---%s----%s---%d", errmsg,__file__,__line__); }} #pragma mark-insert data-(void) Initinsertdata {for (int i = 0; i <; i + +) {//1. Splicing SQL statements NSSt                Ring *name = [NSString stringwithformat:@ "Data--%d", Arc4random_uniform (100)];                int age = Arc4random_uniform (20) + 10;                NSString *sql=[nsstring stringwithformat:@ "INSERT into T_students (name,age) VALUES ('%@ ',%d);", Name,age];        2. Execute SQL statement char *errmsg = NULL; Sqlite3_exec (_db, SQL.        Utf8string, NULL, NULL, &AMP;ERRMSG);        if (errmsg) {//If there is an error message NSLog (@ "Insert data failed--%s", errmsg);  }else {NSLog (@ "Insert data success");      }}} #pragma mark-select query operation-(void) Initselect {//From this table find the data const char *sql= "Sele    CT id,name,age from t_students WHERE age<20; ";        sqlite3_stmt *stmt = NULL; Prepare to work if (SQLITE3_PREPARE_V2 (_db, SQL,-1, &stmt, NULL) = = SQLITE_OK) {//sql Statement no problem NSLog (@ "S        QL Statement No problem "); Each time the Sqlite_step function is called, the stmt points to the next record while (Sqlite3_step (stmt) = = Sqlite_row) {//Take out data//(1) Remove the            0 column field get value (int type value) int ID = Sqlite3_column_int (stmt, 0);            (2) Take out the 2nd column field value (text type value) Const unsigned char *name = Sqlite3_column_text (stmt, 1);            (3) Remove the 2nd column field value int = Sqlite3_column_int (stmt, 2);        printf ("%d%s%d\n", id,name,age);    }}else {NSLog (@ "query statement has a problem, or no data");    }} #pragma mark-delete data-(void) initdelete {const char *sql = "Delete from t_students";    char *errmsg = NULL; Sqlite3_exec (_db, SQL, NULL, NULL, &errmsg);    if (errmsg) {NSLog (@ "Delete failed");    }else {NSLog (@ "Delete succeeded");    }}-(void) initupdata {const char *sql = "Update t_students set name = ' Xiaoming ', age = 16;";    char *errmsg = NULL;    Sqlite3_exec (_db, SQL, NULL, NULL, &AMP;ERRMSG);    if (errmsg) {NSLog (@ "failed to modify");    }else {NSLog (@ "modified successfully"); }} @end

Note: To import libsqlite3.dylib

SQLite Simple to use