FMDB

标签（空格分隔）： iOS FMDB 数据库

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FMDB的构成

• FMDatabase – 表示一个单独的SQLite数据库。 用来执行SQLite的命令。
• FMResultSet – 表示FMDatabase执行查询后结果集合
• FMDatabaseQueue – 如果你想在多线程中执行多个查询或更新，你应该使用该类。这是线程安全的

数据库的创建

#define TESTDB @"TESTDB.sqlite"

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentDirectory = [paths objectAtIndex:0];
NSString *dbPath = [documentDirectory stringByAppendingPathComponent:TESTDB];
NSLog(@"%@",dbPath);
FMDatabase *db = [FMDatabase databaseWithPath:dbPath] ;
_db = db;
if (![db open]) {
NSLog(@"Could not open db.");
return ;
}

操作

创建表

[db executeUpdate:@"CREATE TABLE PersonList (Name text, Age integer, Sex integer, Phone text, Address text)"];

增删改

除了查询以外 全部用 executeUpdate 而且value必须是对象类型

- (IBAction)addDB:(id)sender {
if ([_db open]) {
[_db executeUpdate:@"INSERT INTO PersonList (Name, Age, Sex, Phone, Address) VALUES (?,?,?,?,?)",
@"alex",@20, @0,@"091234567", @"Taiwan, R.O.C"];
[_db close];
}

}
- (IBAction)subDB:(id)sender {



}
- (IBAction)changeDB:(id)sender {
if ([_db open]) {
[_db executeUpdate:@"UPDATE PersonList SET Age = ? WHERE Name = ?",[NSNumber numberWithInt:30],@"alex"];
[_db close];
}

}
- (void)dealloc
{
[_db close];
}

查

FMResultSet 提供了很多方法来获得所需的格式的值： intForColumn: longForColumn: longLongIntForColumn: boolForColumn: doubleForColumn: stringForColumn: dataForColumn: dataNoCopyForColumn: UTF8StringForColumnIndex: objectForColumn:

- (IBAction)searchDB:(id)sender {
if ([_db open]) {
// 1.执行查询语句
FMResultSet *resultSet = [self.db executeQuery:@"SELECT * FROM PersonList"];
// 2.遍历结果
while ([resultSet next]) {
NSString *name = [resultSet stringForColumn:@"Name"];
int age = [resultSet intForColumn:@"Age"];
NSLog(@" %@ %d", name, age);
}
[_db close];
}
}

多线程

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentDirectory = [paths objectAtIndex:0];
NSString *dbPath = [documentDirectory stringByAppendingPathComponent:TESTDB];
FMDatabaseQueue *queue = [FMDatabaseQueue databaseQueueWithPath:dbPath];
[queue inDatabase:^(FMDatabase *db) {

}];