ui18-database operations: SQL FMDB

(a) FMDB open database, CREATE TABLE, query

(b) Execution statement:

(iii) Storage of data, model archiving, anti-archiving, and implementation of the Nscoding protocol an object can be converted to data. In essence, a nscoding protocol is implemented to comply with Nscoding protocol, and the method of implementing the protocol can be transformed into NSData.

(iv) Implementation of the encoding protocol two methods:

(v) Extract the same code, use the method, or call the duplicate code with block, and set the parameters and return values.

1/FOREIGN KEY constraint.

(vi)---Multi-threaded operation in Fmdb

• If you want to do massive operations, you need to use a sub-thread to speed up
• However, the database operation of a large amount of data, such as inserting 100,000 of data, you can open multiple sub-threads to operate, but you must use a synchronization thread, so that multiple threads execute one at a rather than cause database data confusion.
• FMDatabaseQueueUse this class

    //FMDatabaseQueue的创建    FMDatabaseQueue *queue = [FMDatabaseQueue databaseQueueWithPath:path];

• Basic operations

    [queue inDatabase:^(FMDatabase *db) {        [db executeUpdate:@"INSERT INTO t_student(name) VALUES (?)", @"Jack"];        [db executeUpdate:@"INSERT INTO t_student(name) VALUES (?)", @"Rose"];        [db executeUpdate:@"INSERT INTO t_student(name) VALUES (?)", @"Jim"];                FMResultSet *rs = [db executeQuery:@"select * from t_student"];        while ([rs next]) {            // …        }    }];

• Using transactions

    [queue inTransaction:^(FMDatabase *db, BOOL *rollback) {        [db executeUpdate:@"INSERT INTO t_student(name) VALUES (?)", @"Jack"];        [db executeUpdate:@"INSERT INTO t_student(name) VALUES (?)", @"Rose"];        [db executeUpdate:@"INSERT INTO t_student(name) VALUES (?)", @"Jim"];        FMResultSet *rs = [db executeQuery:@"select * from t_student"];        while ([rs next]) {            // …        }    }];

• Transaction rollback
  • *rollback = YES;

ui18-Database operations: SQL FMDB