What is FTS3?

What is FTS3?

FTS3 and FTS4 are SQLite virtual table modules that allows full-text searches to be performed on a set of documents.

What is FTS5?

FTS5 is an SQLite virtual table module that provides full-text search functionality to database applications. To use FTS5, the user creates an FTS5 virtual table with one or more columns. For example: CREATE VIRTUAL TABLE email USING fts5(sender, title, body);

What is a Tokenizer SQLite?

The tokenizer recognizes tokens one by one and passes them on to the parser. Except whitespace is ignored. The only use for whitespace is as a separator between tokens.

What is Rowid in SQLite?

When you create a table without specifying the WITHOUT ROWID option, SQLite adds an implicit column called rowid that stores 64-bit signed integer. The rowid column is a key that uniquely identifies the rows in the table. Tables that have rowid columns are called rowid tables.

What is primary key in sqlite3?

In SQLite, a primary key is a single field or combination of fields that uniquely defines a record. A table can have only one primary key. TIP: While the SQL-89 and SQL-92 standards do not allow a NULL value in a primary key, SQLite does allow a NULL under certain circumstances.

What is full-text in SQL?

Full-Text Search in SQL Server lets users and applications run full-text queries against character-based data in SQL Server tables. Full Text Index helps to perform complex queries against character data. A full-text query returns any document that contain at least one match (also known as a hit).

Can SQLite have multiple primary keys?

Primary keys must contain unique values. A primary key column cannot have NULL values. A table can have only one primary key, which may consist of single or multiple fields. When multiple fields are used as a primary key, they are called a composite key.

Can a primary key be text?

You can not set primary key to text and ntext columns. But you can achiveve the same functionality by setting datatype as a varchar(8000). The difference is this column can now contain at most 8000 chars.

What are the primary key guidelines?

A primary key’s main features are:

• It must contain a unique value for each row of data.
• It cannot contain null values.
• Every row must have a primary key value.

How to create a primary key in T-SQL?

We can Create a Primary Key in 2 ways: 1. SQL Server Management Studio 2. T-SQL: Create Primary while creating a New Table Step 1) Right Click on the Table name. Click on Design. Step 2) Right-click on the Column name. Click on ‘ Set Primary Key’ Result: Course_Id is now a Primary Key. T-SQL: Create a Primary key while creating a New Table.

How many primary keys can a table have in SQL?

A table can have only ONE primary key; and in the table, this primary key can consist of single or multiple columns (fields). The following SQL creates a PRIMARY KEY on the “ID” column when the “Persons” table is created:

How do you create a primary key constraint in SQL?

To allow naming of a PRIMARY KEY constraint, and for defining a PRIMARY KEY constraint on multiple columns, use the following SQL syntax: Note: If you use ALTER TABLE to add a primary key, the primary key column (s) must have been declared to not contain NULL values (when the table was first created).

How long does a FTS3 query take to run?

Using one desktop PC hardware configuration, the query on the FTS3 table returns in approximately 0.03 seconds, versus 22.5 for querying the ordinary table. Of course, the two queries above are not entirely equivalent.