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Expo SQLite iconExpo SQLite

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A library that provides access to a database that can be queried through a WebSQL-like API.


expo-sqlite gives your app access to a database that can be queried through a WebSQL-like API. The database is persisted across restarts of your app.

Platform Compatibility

Android DeviceAndroid EmulatoriOS DeviceiOS SimulatorWeb

Installation

Terminal
npx expo install expo-sqlite

If you're installing this in a bare React Native app, you should also follow these additional installation instructions.

Usage

To-do list app

An example to-do list app is available that uses this module for storage.

Importing an existing database

To open a new SQLite database using an existing .db file you already have, follow the steps below:

1

Install expo-file-system and expo-asset modules:

Terminal
npx expo install expo-file-system expo-asset

2

Create a metro.config.js file at the root of your project with the following contents to include extra asset extensions:

const { getDefaultConfig } = require('expo/metro-config');

const defaultConfig = getDefaultConfig(__dirname);

defaultConfig.resolver.assetExts.push('db');

module.exports = defaultConfig;

3

Use the following function (or similar) to open your database:

async function openDatabase(pathToDatabaseFile: string): Promise<SQLite.WebSQLDatabase> {
  if (!(await FileSystem.getInfoAsync(FileSystem.documentDirectory + 'SQLite')).exists) {
    await FileSystem.makeDirectoryAsync(FileSystem.documentDirectory + 'SQLite');
  }
  await FileSystem.downloadAsync(
    Asset.fromModule(require(pathToDatabaseFile)).uri,
    FileSystem.documentDirectory + 'SQLite/myDatabaseName.db'
  );
  return SQLite.openDatabase('myDatabaseName.db');
}

Executing statements outside of a transaction

You should use this kind of execution only when it is necessary. For instance, when code is a no-op within transactions. Example: PRAGMA foreign_keys = ON;.

const db = SQLite.openDatabase('dbName', version);

db.exec([{ sql: 'PRAGMA foreign_keys = ON;', args: [] }], false, () =>
  console.log('Foreign keys turned on')
);

API

import * as SQLite from 'expo-sqlite';

Classes

SQLError

SQLError Properties

message

Type: string


CONSTRAINT_ERR

Type: number


DATABASE_ERR

Type: number


QUOTA_ERR

Type: number


SYNTAX_ERR

Type: number


TIMEOUT_ERR

Type: number


TOO_LARGE_ERR

Type: number


UNKNOWN_ERR

Type: number


VERSION_ERR

Type: number


Methods

SQLite.openDatabase(name, version, description, size, callback)

NameTypeDescription
namestring

Name of the database file to open.

version
(optional)
string-
description
(optional)
string-
size
(optional)
number-
callback
(optional)
(db: WebSQLDatabase) => void-

Open a database, creating it if it doesn't exist, and return a Database object. On disk, the database will be created under the app's documents directory, i.e. ${FileSystem.documentDirectory}/SQLite/${name}.

The version, description and size arguments are ignored, but are accepted by the function for compatibility with the WebSQL specification.

Returns

  • WebSQLDatabase

Interfaces

Database

Database objects are returned by calls to SQLite.openDatabase(). Such an object represents a connection to a database on your device.

Database Methods

transaction(callback, errorCallback, successCallback)

NameTypeDescription
callbackSQLTransactionCallback

A function representing the transaction to perform. Takes a Transaction (see below) as its only parameter, on which it can add SQL statements to execute.

errorCallback
(optional)
SQLTransactionErrorCallback

Called if an error occurred processing this transaction. Takes a single parameter describing the error.

successCallback
(optional)
() => void

Called when the transaction has completed executing on the database.


Execute a database transaction.

Returns

  • void

Database Properties

NameTypeDescription
versionstring-

SQLResultSetRowList

SQLResultSetRowList Methods

item(index)

NameTypeDescription
indexnumber

Index of row to get.


Returns the row with the given index. If there is no such row, returns null.

Returns

  • any

SQLResultSetRowList Properties

NameTypeDescription
_arrayany[]

The actual array of rows returned by the query. Can be used directly instead of getting rows through rows.item().

lengthnumber

The number of rows returned by the query.


SQLTransaction

A SQLTransaction object is passed in as a parameter to the callback parameter for the db.transaction() method on a Database (see above). It allows enqueuing SQL statements to perform in a database transaction.

SQLTransaction Methods

executeSql(sqlStatement, args, callback, errorCallback)

NameTypeDescription
sqlStatementstring

A string containing a database query to execute expressed as SQL. The string may contain ? placeholders, with values to be substituted listed in the arguments parameter.

args
(optional)
(null | string | number)[]

An array of values (numbers, strings or nulls) to substitute for ? placeholders in the SQL statement.

callback
(optional)
SQLStatementCallback

Called when the query is successfully completed during the transaction. Takes two parameters: the transaction itself, and a ResultSet object (see below) with the results of the query.

errorCallback
(optional)
SQLStatementErrorCallback

Called if an error occurred executing this particular query in the transaction. Takes two parameters: the transaction itself, and the error object.


Enqueue a SQL statement to execute in the transaction. Authors are strongly recommended to make use of the ? placeholder feature of the method to avoid against SQL injection attacks, and to never construct SQL statements on the fly.

Returns

  • void

WebSQLDatabase

Extends: Database

Database objects are returned by calls to SQLite.openDatabase(). Such an object represents a connection to a database on your device.

WebSQLDatabase Methods

closeAsync()

Close the database.

Returns

  • void

deleteAsync()

Delete the database file.

The database has to be closed prior to deletion.

Returns


exec(queries, readOnly, callback)

NameTypeDescription
queriesQuery[]-
readOnlyboolean-
callbackSQLiteCallback-

Returns

  • void

Window

Window Properties

NameTypeDescription
openDatabase
(optional)
(name: string, version: string, displayName: string, estimatedSize: number, creationCallback: DatabaseCallback) => Database-

Types

DatabaseCallback()

NameTypeDescription
databaseDatabase-

Query

NameTypeDescription
argsunknown[]-
sqlstring-

ResultSet

ResultSet objects are returned through second parameter of the success callback for the tx.executeSql() method on a SQLTransaction (see above).

NameTypeDescription
insertId
(optional)
number

The row ID of the row that the SQL statement inserted into the database, if a row was inserted.

rows{ [column]: any }-
rowsAffectednumber

The number of rows that were changed by the SQL statement.

ResultSetError

NameTypeDescription
errorError-

SQLResultSet

NameTypeDescription
insertId
(optional)
number

The row ID of the row that the SQL statement inserted into the database, if a row was inserted.

rowsSQLResultSetRowList-
rowsAffectednumber

The number of rows that were changed by the SQL statement.

SQLStatementCallback()

NameTypeDescription
transactionSQLTransaction-
resultSetSQLResultSet-

SQLStatementErrorCallback()

NameTypeDescription
transactionSQLTransaction-
errorSQLError-

SQLTransactionCallback()

NameTypeDescription
transactionSQLTransaction-

SQLTransactionErrorCallback()

NameTypeDescription
errorSQLError-

SQLiteCallback()

NameTypeDescription
error
(optional)
Error | null-
resultSet
(optional)
(ResultSetError | ResultSet)[]-