How to create/restore a slave using GTID replication in MySQL 5.6
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IndexedDB is a way for you to persistently auto transazioni binaries data inside a user's browser. Because it lets you create web applications with rich query abilities regardless of network availability, these applications can work both online and offline.
IndexedDB is useful for applications that store a large amount of data for example, a catalog of DVDs in a lending library and applications that don't need persistent internet connectivity to work for example, mail clients, to-do lists, and notepads. This introduction discusses essential concepts and terminology in IndexedDB. It gives you the big picture and explains key concepts.
IndexedDB lets you store and retrieve objects that are indexed with a "key. Like most web storage solutions, IndexedDB follows a same-origin policy. So while you can access stored data within a domain, you cannot access data across different domains. It used to include a synchronous version also, for use in web workers, but this was removed from the spec due to lack of interest by the web community. If you have assumptions from working with other types of databases, you might get thrown off when working with IndexedDB.
So keep the following important concepts in mind:. IndexedDB databases store key-value pairs. The values can be complex structured objects, and keys can be properties of those objects.
You can create indexes that use any property of the objects for quick searching, as well as sorted enumeration. Keys can be binary objects. IndexedDB is built on a transactional database model. Everything you do in IndexedDB always happens in the context of a transaction. The IndexedDB API provides lots of objects that represent indexes, tables, cursors, and so on, but each of these is tied to a particular transaction. Thus, you cannot execute commands or open cursors outside of a transaction.
Transactions have a well-defined lifetime, so attempting to use a transaction after it has completed throws exceptions. Also, transactions auto-commit and cannot be committed manually. This transaction model is really useful when you consider what might happen if a user opened two instances of your web app in two different tabs simultaneously.
Without transactional operations, the two instances could interfere with each other's modifications. If you are not familiar with transactions in a database, read the Wikipedia article on transactions. Also see transaction under the Definitions section. The API doesn't give you data by returning values; instead, you have to pass a callback function.
You don't "store" a value into the database, or "retrieve" a value out of the database through synchronous means. Instead, you "request" that a database operation happens.
You get notified by a DOM event when the operation finishes, and the type of event you get lets you know if the operation succeeded or failed. Auto transazioni binaries sounds a little complicated at first, but there are sanity measures baked in.
IndexedDB uses a lot of requests. Requests are objects that receive the success or failure DOM events that were mentioned previously. Success events don't bubble up auto transazioni binaries they can't be canceled. Error events, on the other hand, do bubble, and can be cancelled. This is quite important, as error events abort whatever transactions they're running in, unless they are cancelled.
Each object store can have a collection of indexes that makes it efficient to query and iterate across. If you are not familiar with object-oriented database management systems, read the Wikipedia article auto transazioni binaries object database.
It uses queries on an index that produces a cursor, which you use to iterate across the result set. IndexedDB adheres to a same-origin policy. An origin is the domain, application layer protocol, and port of a URL of the document where the script is being executed.
Each origin has its own associated set of databases. Every database auto transazioni binaries a name auto transazioni binaries identifies it within an origin. The security boundary imposed on IndexedDB prevents applications from accessing data with a different origin. For example, while an app or a page in http: When a database is first created, its version is the integer auto transazioni binaries if not specified otherwise. Each database can have only one version auto transazioni binaries any given time.
In this case the complete event is fired after the OS has been told to write the data but potentially before that data has actually been flushed to disk. The event may thus be delivered quicker than before, however, there exists a small chance that the entire transaction will be lost if the OS crashes or there is a loss of system power before the data is flushed to disk.
Since such catastrophic events are rare, most consumers should not need to concern themselves further. In Firefox, if you wish to ensure durability for some reason e.
This is currently experimental, and can only be used if the dom. The mechanism by which data is stored in the database. The object store persistently holds records, which are key-value pairs. Records within an object store are sorted according to the keys in an ascending order.
Every object store must have a name auto transazioni binaries is unique within its database. The object store can optionally have a key generator and a key path.
If the object store has a key path, it is using in-line keys auto transazioni binaries otherwise, it is using auto transazioni binaries keys. An atomic set of data-access and data-modification operations on a particular database.
It is how you interact with the data in a database. In fact, any reading or changing of data in the database must happen in a transaction. A database connection can have several active transactions associated with it at a time, so long as the writing transactions do not have overlapping scopes. The scope of transactions, which is defined at creation, determines which object stores the transaction can interact with and remains constant for the lifetime of the transaction.
So, for example, if a database connection already has a writing transaction with a scope that just covers the flyingMonkey object store, you can start a second transaction with a scope of the unicornCentaur and unicornPegasus object stores. As for reading transactions, you can have several of them — even overlapping ones.
Transactions are expected to be short-lived, so the browser can terminate a transaction that takes too long, in order to free up storage resources that the long-running transaction has locked. You can abort the transaction, which rolls back the changes made to the auto transazioni binaries in the transaction.
And you don't even have to wait for the transaction to start or be active auto transazioni binaries abort it. The three modes of transactions are: The only auto transazioni binaries to create and delete object stores and indexes is by using a versionchange transaction.
To learn more about transaction types, see the reference article for IndexedDB. Because everything happens within a transaction, it is a very important concept in IndexedDB. To learn more about transactions, especially on how they relate to versioning, auto transazioni binaries IDBTransactionwhich also has reference documentation.
An index is a specialized object store for looking up records in another object store, called the referenced object store. The index is a persistent key-value storage where the value part of its records is the key part of a record in the referenced object store.
The records in an index are automatically populated whenever records in the referenced auto transazioni binaries store are inserted, updated, or deleted. Each record in an index can point to only one record in its referenced object store, but several indexes can reference the same object store.
When the object store changes, all indexes that refer to the object store are automatically updated. Alternatively, you can also look up records in an object auto transazioni binaries using the key.
To learn more on using indexes, see Using IndexedDB. A data value by which stored values are organized and retrieved in the object store. The object store can auto transazioni binaries the key from one of three sources: The key must be of a data type that has auto transazioni binaries number that is greater than the one before it.
Each record in an object store must have a key that is unique within the same store, so you cannot have multiple records with the same key in a given object store. A key can be one of the following types: For arrays, the key can range from an empty value to infinity.
A continuous interval over some data type used for auto transazioni binaries. Records can be retrieved from object stores and indexes using keys or a range of keys.
You can limit or filter the range using lower and upper bounds. For example, you can iterate over all values of a key between x and y. IndexedDB is designed to cover most cases that need client-side storage.