创建表 snapshot 新增collection字段设置默认值为0 如果不设置默认值去掉DEFAULT '0'即可
#define CREATE_TABLE_SNAPSHOT @"CREATE TABLE IF NOT EXISTS snapshot(id INTEGER PRIMARY KEY AUTOINCREMENT, dev_uid TEXT, file_path TEXT, time REAL)"
#define CREATE_TABLE_SNAPSHOT_ADD_COLUMN @"CREATE TABLE IF NOT EXISTS snapshot(id INTEGER PRIMARY KEY AUTOINCREMENT, dev_uid TEXT, file_path TEXT, time REAL, collection INTEGER)"
if (database != NULL) {
if (![database tableExists:@"snapshot"]) {
NSLog(@"不存在表");
if (![database executeUpdate:CREATE_TABLE_SNAPSHOT_ADD_COLUMN]) NSLog(@"Can not create table snapshot");
} else {
if ([database columnExists:@"snapshot" columnName:@"collection"])
{
NSLog(@"存在");
}
else
{
NSLog(@"不存在字段");
if ([database executeUpdate:@"ALTER TABLE snapshot ADD COLUMN collection INTEGER DEFAULT '0'"]) {
NSLog(@"字段添加成功");
}
}
}
}