Database Fmdb-sql

1, first to import the third-party class library fmdatabase.

2. Get the sandbox address where the database files are stored.

#pragma mark-Create a database

-(void) Createandinitdatabase {

NSString *path = [NSString stringwithformat:@ "%@/documents/test.db", Nshomedirectory ()];

If the database file exists, open directly, or if not, create

_database = [[Fmdatabase alloc] initwithpath:path];

if (!_database.open) {

NSLog (@ "Open failed");

Return

}

NSLog (@ "open successfully");

Create

NSString *sql = @ "CREATE table if not exists stuinfo (SID varchar (+), username varchar (+), password varchar (32))";

Perform

Note: Execute SQL query statements using ExecuteQuery

Executing non-query statements using the Executeupdata method

BOOL B = [_database executeupdate:sql];

NSLog (@ "CREATE table%d", b);

}

#pragma mark-Insert data

-(void) InsertData {

NSString *sid = @ "01";

NSString *username = @ "Dage";

NSString *password = @ "1234";

SQL execution, using instead of changing data

NSString *sql = @ "INSERT into Stuinfo (Sid,username,password) VALUES (?,?,?)";

BOOL B = [_database Executeupdate:sql,sid,username,password];

NSLog (@ "Insert data =%d", b);

}

#pragma mark-query data

-(void) Searchdata {

NSString *sql = @ "Select *from stuinfo";

Returns the result value (understood as EXECL table, multi-row multi-column series data structure)

Fmresultset *resultset = [_database executequery:sql];

while ([ResultSet next]) {

NSLog (@ "sid =%@ name =%@ PW =%@", [ResultSet stringforcolumnindex:0],[resultset stringforcolumnindex:1],[resultset Stri Ngforcolumnindex:2]);

}

}

#pragma mark-Modify data

-(void) Updatadata {

NSString *username = @ "xiyoushijing";

NSString *sql = @ "Update stuinfo set sid= ' where username=?";

BOOL B = [_database executeupdate:sql,username];

NSLog (@ "Modify data =%d", b);

}

#pragma mark-delete data

-(void) DeleteData {

NSString *username = @ "xiyoushijing";

NSString *sql = @ "Delete from Stuinfo where username=?";

BOOL B = [_database executeupdate:sql,username];

NSLog (@ "Delete data =%d", b);

}

Database Fmdb-sql