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Sqlite

Table of contents

  1. Sqlite
    1. Sqlite.connect(string: database)
    2. sqlite.execute(string: query, list: arguments -> optional)
      1. Arguments
    3. sqlite.close()

Sqlite

To make use of the Sqlite module an import is required.

Note: Unlike SQLite and most other libraries, foreign keys are enabled by default when a connection is opened.

import Sqlite;

Sqlite.connect(string: database)

This opens a connection to a SQLite database. Returns a Result type and on success wraps an abstract SQLite type.

Note: You can pass “:memory:” to open the SQLite database in memory rather than a file.

Sqlite.connect(":memory:").unwrap();
Sqlite.connect("my/database/file.db").unwrap();

sqlite.execute(string: query, list: arguments -> optional)

The execute method is ran on the abstract that is returned from .connect rather than the Sqlite module, hence the lower case sqlite. The execute method executes an SQL query and can return one of 3 values.

A Result type is returned, the value being wrapped depends on the query: If the query is a type that does not return data (such as UPDATE / DELETE), then nil is wrapped on successful queries. If the query is a SELECT statement then a list is wrapped on successful queries (empty list for a select query that returns no rows).

sqlite.execute("UPDATE mytable SET mycolumn = 10"); // <Result Suc>
var query = sqlite.execute("UPDATE unknown_table SET mycolumn = 10"); // <Result Err>
print(query.unwrapError()); // no such table: unknown_table

Arguments

Passing user input to a query should always be done through the method of binding parameters and never through string interpolation, otherwise your application will be at risk to SQL injection. Binding values to placeholders is incredibly simple.

sqlite.execute("SELECT * FROM mytable WHERE mycolumn = ?", [
    "test"
]);

The ? will take the value of the item in the list. If there are multiple placeholders then it is done by index, for example.

sqlite.execute("SELECT * FROM mytable WHERE mycolumn = ? AND mycolumn1 = ?", [
    "test",
    "next value"
]);

The first ? matches with the first value in the list, and the second ? with the second value in the list, and so on.

sqlite.close()

Closes the database.

sqlite.close();

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