"IOS" Using SQLite and Fmdb

SQLite in iOS is exactly the same as in Android, except that the calling method is different. If a single call from the Android package is better than a set of helper, and iOS native C language of several functions in operation, more trouble. However, the introduction of third-party framework Fmdb, the use of more convenient.

First, the basic use of SQLite

Steps to use:

1.Import System Framework(Clanguage). (libsqlite3)2.header File#import <sqlite3.h.3. Sqlite3_open(filename.utf8string, &_DB); Open or create a data *_dbDefine yourself aSqlite3the member variable.to be used when checking.4.sqlite3_exec(_db, SQL, NULL, null,&error);*This function can be used toInsert,Delete,UpdateOperation.5.Query OperationsSelect.*SQLITE3_PREPARE_V2(_db, SQL,-1, &stmt, NULL);prepare before you make a query,DetectionSQLstatement is correct.*sqlite3_step (stmt)extracting data from a query,extract one at a time.*Sqlite3_column_text (stmt, 0)Remove Section0columns of data.
look directly at the code to make it easier to understand:To Create or open a database:

   0. Get the file address    nsstring *path = [Nssearchpathfordirectoriesindomains (nsdocumentdirectory, Nsuserdomainmask, YES) Lastobject];    NSString *filename = [path stringbyappendingpathcomponent:@ "T_student.sqlite"];    1. Open or create a database    //(1. If the database does not exist, it will automatically create the database and open, 2. If the database store will automatically open the database)    int result = Sqlite3_open ( Filename.utf8string, &_db);    if (result = = SQLITE_OK) {        NSLog (@ "Open database succeeded");        2. CREATE TABLE        /**         sqlite3 Pass Open database         sql: Database statement to execute         */        const char *sql = "CREATE table IF not EXISTS t _student (ID integer PRIMARY KEY autoincrement, name TEXT NOT NULL, age INTEGER not null); ";        char *error = nil;        Execute SQL statement in DB database        sqlite3_exec (self.db, SQL, NULL, NULL, &ERROR);        if (error) {            NSLog (@ "Failed to create TABLE");        } else        {            NSLog (@ "CREATE table succeeded");        }    } else    {         NSLog (@ "Open database Failed");    }

Insert data: (update, delete similar)

1. Splicing Insert SQL statement        nsstring *name = [NSString stringwithformat:@ "jonathan-%d", I];        int age = Arc4random_uniform (+);        NSString *sql = [NSString stringwithformat:@ "INSERT into T_student (name, age) VALUES ('%@ ',%d);", name, age];        char *error = nil;        2. Execute the INSERT SQL statement        sqlite3_exec (self.db, SQL. Utf8string, NULL, NULL, &ERROR);        if (error) {            NSLog (@ "Add failed");        } else        {            NSLog (@ "add success");        }

Query data:

const char *sql = "SELECT Name, age from T_student;"; /    Char *error = nil;//    sqlite3_exec (self.db, SQL, NULL, NULL, &ERROR);    Sqlite3_stmt *stmt; Used to extract data    //1. Before making the query, check that the SQL statement is correct    int result = SQLITE3_PREPARE_V2 (self.db, SQL,-1, &stmt, NULL);    if (result = = SQLITE_OK) {//Ready to complete, no error        //2. Extract the data from the query to stmt, one at a time        ///If the return value is Sqlite_row, it represents the extraction to a record while       ( Sqlite3_step (stmt) = = Sqlite_row)       {           //3. Remove data from the No. 0 column in the extracted Records (data)           const unsigned char *name = Sqlite3_column _text (stmt, 0);           int age = Sqlite3_column_int (stmt, 1);           NSLog (@ "%s%d", name, age);       }    }

second, the use of Fmdbthe benefit of Fmdb is the encapsulation of the basic C library for ease of use. At the same time, it also provides the methods of the multi-threaded operation database to read dirty data and so on.
Frame Address: Https://github.com/ccgus/fmdb

Use: (Needfmdatabase *dbmember Variables)Create or Open:

0. Get the sandbox path    nsstring *path = [Nssearchpathfordirectoriesindomains (nsdocumentdirectory, Nsuserdomainmask, YES) Lastobject];    NSString *filename = [path stringbyappendingpathcomponent:@ "T_student.sqlite"];    1. Obtain the database object    self.db = [Fmdatabase databasewithpath:filename];        2. Open    the database if ([self.db Open]) {        NSLog (@ "open successfully");        2.1 CREATE TABLE       BOOL success =  [self.db executeupdate:@ "CREATE table IF not EXISTS t_student (id INTEGER PRIMARY KEY AUT Oincrement NOT NULL, name TEXT is not NULL, the age INTEGER is not null); "];        if (success) {            NSLog (@ "CREATE table succeeded");        } else        {            NSLog (@ "Failed to create TABLE");}    } else    {        NSLog (@ "Open failed");    }

Insert operation:(update, delete, similar to this)

BOOL success = [Self.db executeupdate:@ "INSERT into T_student (name, age) VALUES (?,?);", @ "Xuneng", @ (10)];//Note You can only stitch object types C0/>if (Success) {            NSLog (@ "add success");        } else        {            NSLog (@ "Add failed");        }

Inquire:

1. Query    fmresultset *set = [self.db  executequery:@ "select * from T_student;];        2. Remove the data    while ([set next]) {                //Remove name//       NSString *name = [set stringforcolumnindex:1];        Remove Age/       int. = [set intforcolumnindex:2];        NSString *name = [set stringforcolumn:@ "name"];        int age = [Set intforcolumn:@ ' age '];        NSLog (@ "name =%@, age =%d", name, age);    }

Fmdb can also define the operation queue Fmdatabasequeue, this queue is thread-safe. (Fmdatabase is not thread-safe)
It can also open thingsand submit things. Very convenient to use.
can refer to Https://github.com/ccgus/fmdb on the study, written in quite detailed.

Reprint Please specify Source: http://blog.csdn.net/xn4545945

"IOS" Using SQLite and Fmdb