SQLite additions and deletions to search

//Basic Steps//1. Open the database//2. Processing Data//3. Close the database 

// first SET global variable lazy var documentspath:string = {        true)        return paths.first!     } ()    // pointer    var db:opaquepointer? = Nil    var stmt: Opaquepointer? = Nil

//Create or open a databasefunc createoropendatabase () {print ("\ (nshomedirectory ())")                //Create the database file path and change to the UTF-8 typeLet path:nsstring ="\ (documentspath)/test.sqlite3"  asnsstring let filename=path.utf8string//determines whether the open database is successful (automatically generated if no database is created), does not succeed print the input "Create or Open failed ..." and closes the database        ifSqlite3_open (filename, &db)! =SQLITE_OK {print ("Create or Open failed ...") sqlite3_close (db)}}//Create student Tablesfunc createtable () {//splicing SQL statements and turning to UTF-8Letstring: NSString ="CREATE table if not exists Student (ID integer primary key autoincrement, sno text, name text, score integer)"Let SQL=string. utf8string//Execute SQL statement        ifSQLITE3_EXEC (DB, SQL, nil, nil, nil)! =SQLITE_OK {print ("CREATE TABLE failed ...") sqlite3_close (db)}}//new operations for SLQfunc insertstudent (sno:string, name:string, score:int) {//Preparing SQL statementsLetstring: NSString ="INSERT INTO Student (SNO, name, score) VALUES (?,?,?)"Let SQL=string. utf8string//Parsing SQL text statements//SQLITE3_PREPARE_V2 parsing//parameter 1: current database pointer//parameter 2: SQL statement to parse (ends with 0 by default)//Parameter 3: Because the SQL statement ends with 0 by default, in order to go out that 0, it is -1//parameter 4: Another pointer is used for parsing and storing, and the last parameter is forgotten, you can write nil directly.        ifSQLITE3_PREPARE_V2 (DB, SQL,-1, &stmt, nil)! =SQLITE_OK {sqlite3_close (db) Print ("\ (Sno), insert failed ...")        }                //Binding ParametersLet Csno = (sno asnsstring). utf8string Let CNAME= (name asnsstring). Utf8string Sqlite3_bind_text (stmt,1, Csno,-1, nil) sqlite3_bind_text (stmt,2, CNAME,-1, nil) sqlite3_bind_int (stmt,3, Int32 (score))//Execute SQL statement        ifSqlite3_step (stmt) = =sqlite_error {sqlite3_close (db) Print ("\ (Sno), insert failed ...")        } Else {            //Freeing Resourcessqlite3_finalize (stmt)}}//Modify student Datafunc updatestudent () {//Preparing SQL statementsLetstring: NSString ="Update Student Set score = + where name like ' a% '"Let SQL=string. utf8string//Execute SQL statement//sqlite3_exec The following three parameters can not be closed, write nil on it.        ifSQLITE3_EXEC (DB, SQL, nil, nil, nil)! =SQLITE_OK {sqlite3_close (db) Print ("update failed ...")        }    }        //Delete student Datafunc deletestudents () {//Preparing SQL statementsLetstring: NSString ="Delete from Student where score <"Let SQL=string. utf8string//Execute SQL statement        ifSQLITE3_EXEC (DB, SQL, nil, nil, nil)! =SQLITE_OK {sqlite3_close (db) Print ("Delete Failed ...")        }    }

Summary:Additions and deletions (if no parameters, then the 2nd, 3 steps do not have to write)1: Preparing SQL statementssuch as: let string:nsstring = "INSERT into Student (SNO, name, score) VALUES (?,?,?)"2: Parse SQL statements such as: SQLITE3_PREPARE_V2 (DB, SQL,-1, &stmt, nil)3: Binding Parameterssuch as: let Csno = (sno as NSString). Utf8stringSqlite3_bind_text (stmt, 1, Csno,-1, nil)4 execution statements such as: Sqlite3_step (stmt)5: Releasing resources such as: Sqlite3_finalize (stmt)  Enquiry1: Preparing SQL statements2: Parsing SQL statements3: Execute SQL statementget data for each record (some character types also need to be converted to display the results you want)Sqlite3_column_text (stmt, 0)4: Freeing up resources

SQLite additions and deletions to search