Marks an Entity annotated class as a FTS5 entity. This class will have a mapping SQLite FTS5 table in the database.

FTS5 is a SQLite virtual table module that allows full-text searches to be performed on a set of documents.

An FTS entity table always has a column named rowid that is the equivalent of an INTEGER PRIMARY KEY. Therefore, an FTS entity can only have a single property annotated with PrimaryKey, it must be named rowid and must be of INTEGER affinity. The property can be optionally omitted in the class but can still be used in queries.

All properties in an FTS entity are of TEXT affinity, except the 'rowid' property.

Example:

@Entity
@Fts5
data class Mail (
  @PrimaryKey
  @ColumnInfo(name = "rowid")
  val rowId: Long,
  val subject: String,
  val body: String
)

Warning: The availability of FTS5 is based on the driver used for the database. For Android specifically the androidx.sqlite.driver.bundled.BundledSQLiteDriver supports FTS5.

See also
Entity
Dao
Database
PrimaryKey
ColumnInfo

Summary

Public constructors
Fts5(
    tokenizer: String,
    tokenizerArgs: Array<String>,
    contentEntity: KClass<*>,
    contentRowId: String,
    prefix: IntArray,
    hasColumnSize: Boolean,
    detail: FtsOptions.Detail,
    notIndexed: Array<String>
)
Cmn

Public properties
KClass<*>

The external content entity who's mapping table will be used as content for the FTS table.
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String

The column name to be used as 'content_rowid'.
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FtsOptions.Detail

The 'detail' option affects what is stored in the virtual table.
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Boolean

Enable or disable storing column sizes.
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Array<String>

The list of column names on the FTS table that won't be indexed.
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IntArray

The list of prefix sizes to index.
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String

The tokenizer to be used in the FTS table.
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Array<String>

Optional arguments to configure the defined tokenizer.
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Public constructors

Fts5

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Added in 3.0.0-alpha02
Fts5(
    tokenizer: String = TOKENIZER_UNICODE61,
    tokenizerArgs: Array<String> = [],
    contentEntity: KClass<*> = Any::class,
    contentRowId: String = "",
    prefix: IntArray = [],
    hasColumnSize: Boolean = true,
    detail: FtsOptions.Detail = FtsOptions.Detail.FULL,
    notIndexed: Array<String> = []
)

Public properties

contentEntity

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val contentEntity: KClass<*>

The external content entity who's mapping table will be used as content for the FTS table.

Declaring this value makes the mapping FTS table of this entity operate in "external content" mode. In such mode the FTS table does not store its own content but instead uses the data in the entity mapped table defined in this value. This option allows FTS5 to forego storing the text being indexed which can be used to achieve significant space savings.

In "external mode" the content table and the FTS table need to be synced. Room will create the necessary triggers to keep the tables in sync. Therefore, all write operations should be performed against the content entity table and not the FTS table.

The content sync triggers created by Room will be removed before migrations are executed and are re-created once migrations are complete. This prevents the triggers from interfering with migrations but means that if data needs to be migrated then write operations might need to be done in both the FTS and content tables.

See the External Content FTS5 Tables documentation for details.

Returns
KClass<*>

The external content entity.

contentRowId

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val contentRowId: String

The column name to be used as 'content_rowid'.

Declaring this value without setting contentEntity is an error.

For details, see the content_rowid= option documentation.

Returns
String

The column name to be used as 'content_rowid'.

detail

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val detail: FtsOptions.Detail

The 'detail' option affects what is stored in the virtual table.

Using values other than FtsOptions.Detail.FULL will reduce the space consumed but will also affect the FTS capabilities and efficiency. The default value is FtsOptions.Detail.FULL.

For details, see the detail= option documentation.

Returns
FtsOptions.Detail

The 'detail' option.

hasColumnSize

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val hasColumnSize: Boolean

Enable or disable storing column sizes. Defaults to true.

For details, see the columnsize= option documentation.

Returns
Boolean

The 'columnsize' option.

notIndexed

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val notIndexed: Array<String>

The list of column names on the FTS table that won't be indexed.

For details, see the UNINDEXED column option documentation.

Returns
Array<String>

A list of column names that will not be indexed by the FTS extension.

prefix

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val prefix: IntArray

The list of prefix sizes to index.

For details, the prefix= option documentation.

Returns
IntArray

A list of non-zero positive prefix sizes to index.

tokenizer

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val tokenizer: String

The tokenizer to be used in the FTS table.

The default value is FtsOptions.TOKENIZER_UNICODE61. Tokenizer arguments can be defined with tokenizerArgs.

If a custom tokenizer is used, the tokenizer and its arguments are not verified at compile time.

For details, see SQLite tokenizers documentation

Returns
String

The tokenizer to use on the FTS table. Built-in available tokenizers are FtsOptions.TOKENIZER_UNICODE61, FtsOptions.TOKENIZER_PORTER, FtsOptions.TOKENIZER_ASCII and FtsOptions.TOKENIZER_TRIGRAM.
See also

tokenizerArgs

Cmn 
val tokenizerArgs: Array<String>

Optional arguments to configure the defined tokenizer.

Tokenizer arguments are a white-space series of values represented on this annotation value list. For example, tokenizerArgs = ["separators", "'.'"] defines the dot character as an additional separator when using the FtsOptions.TOKENIZER_UNICODE61 tokenizer.

The available arguments that can be defined depend on the tokenizer defined, see the SQLite tokenizers documentation for details.

Returns
Array<String>

A list of tokenizer arguments strings.