Sqlite3 database operations (iPhone Development)

The following is an operation on the sqlite3 database. The first step is to import the class, which is the most basic, but do not forget. I handled the operations on the database separately. I looked comfortable and understood that it would take a long time to call the database directly when necessary. I can also have a proxy, but I have never studied it, let's take a good look at this in the future. Let's summarize this for your convenience. If you forget to look for it, you don't have to forget it soon!

# Import </usr/include/sqlite3.h> # define kfilename @ "data. sqlite3 "1. open Database Operation-(void) opendb {nsarray * paths = nssearchpathfordirectoriesindomains (nsdocumentdirectory, nsuserdomainmask, yes); nsstring * documentsdirectory = [paths objectatindex: 0]; nsstring * datafilepath = [documentsdirectory stringbyappendingpathcomponent: kfilename]; If (sqlite3_open ([datafilepath utf8string], & database )! = Sqlite_ OK) {sqlite3_close (database) ;}} 2. create a table, structure, type-(void) initdb {char * errormsg; nsstring * SQL = @ "CREATE TABLE if not exists user (user_id integer primary key, username text, password text); "; if (sqlite3_exec (Database, [SQL utf8string], null, null, & errormsg )! = Sqlite_ OK) {sqlite3_close (database) ;}} 3. execute the add method-(void) insertusername :( nsstring *) username insertpassword :( nsstring *) password {[self opendb]; // call to open the database [self initdb]; // call the create table char * errormsg; char * update = "insert or replace into user (username, password) values (?,?); "; // Add statement nsstring * SQL = [nsstring stringwithformat: @" select username, password from user "]; // query statement SQL = @" delete from user ;"; // Delete the statement sqlite3_stmt * Statement; If (statement (Database, update,-1, & statement, nil) = sqlite_ OK) {sqlite3_bind_text (statement, 1, [username utf8string], -1, sqlite_transient); sqlite3_bind_text (statement, 2, [Password utf8string],-1, sqlite_transient);} If (sqlite3_s TEP (statement )! = Sqlite_done) nsassert1 (0, @ "error updating table: % s", errormsg); sqlite3_finalize (statement); sqlite3_close (database );}