SQLite

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SQLite is included in version 1.80.8193.14.

For SQL functions see the SQL Functions category. For the datatype see sqlquery.

For further information about sqlite refer to their website.

This page contains a copy of the documentation included in the game for now. Further tutorials may be added in the future.

Patch Remarks

Full access to the sqlite API has been added.

You can access the following databases:

  • Campaign: Databases spanning modules and savegames, living in database/.
  • Module: A database attached to the running module, persisted to savegames.
  • Player: Each player character has a database attached that gets saved to the character .bic file when saving to a vault (local/server), or exporting the character in singleplayer. It also gets saved to savegames.

Please note: This is an advanced feature, and requires a solid understanding of SQL to make robust and effective use of.

SQLite Support

This subsystem provides access to various sqlite databases that can be found within the game.

Use of this subsystem requires at least basic knowledge of SQL.

The following databases can be accessed:

  • Campaign:
    • Access to all campaign databases is provided; however, the system will not let you write to the builtin tables used by the campaignDB system. (You can still read them, though no guarantee on data format stability is given. To do this create the query using SqlPrepareQueryCampaign and select from "db").
  • This data is written to the database/ directory in the player's user home, so it persists even if the user quits the game without saving, or runs a different module.
  • Module:
    • Each running module has a sqlite database attached to it, that gets persisted to savegames.
    • This data is lost unless the player saves the game.
  • Player:
    • Each player character has a database attached that gets saved to the character .bic file when saving to a vault (local/server), or exporting the character in singleplayer.
    • It also gets saved to savegames.

The functions to run queries models after the sqlite C API.

Basics

Any query you run is encapsulated into a `sqlquery` type variable. This variable can be obtained by "preparing a statement" against a specific database.

SqlPrepareQueryObject(), SqlPrepareQueryCampaign()

Note: This example, and the following, assume the presented tables with appropriate columns exist. By default, none of the databases provided will have any DDL defined. You need to create all tables, views, triggers, etc. yourself.

Example:

    sqlquery myquery = SqlPrepareQueryObject(GetModule(), "select data, y from vectors where x > @x and name = @name");

There are currently two functions to prepare queries (and thus gain access to a database).

SqlPrepareQueryObject() can be called with GetModule() as the first parameter to access the module database. It can also be called with a player character object, to access the player-specific database. All other objects will error out, and no query will be prepared.

SqlPrepareQueryCampaign() can be called with any valid campaign database name.

Once you have a prepared statement (that did not error out, which you can check via SqlGetError()), you can optionally bind parameters to it.

Parameter binding is the sane and modern way to inject variables into a query via. SqlBindInt(), SqlBindFloat(), SqlBindString(), SqlBindVector()

REALLY IMPORTANT NOTE:

  • Parameter binding ensures that no injection of unwanted content can happen, as the bound variables are properly escaped for you.
  • Don't roll your own escape function.
  • Always use binds, NEVER concatenate values directly into your SQL query. Especially not strings, and especially especially not user-supplied strings.

Example:

    SqlBindFloat(myquery, "@x", 5.0f);
    SqlBindString(myquery, "@name", GetName(oPlayer));

The name of the bound parameter is up to you, as long as it starts with @ or : and is a simple identifier (no special characters).

Once you have bound all parameters, you can execute the query. This is done via SqlStep().

SqlStep() will return TRUE, as long as your query is returning rows for you to read.

Note: Even for queries you don't expect to return rows (for example, INSERT); you need to call SqlStep once to actually execute the query. In this case, SqlStep will return FALSE (since there is no row data).

Example:

while (SqlStep(x))
{
    SendMessageToPC(oPlayer, "Your data: " + SqlGetString(x, 0));
    SendMessageToPC(oPlayer, "Your y offset: " + FloatToString(SqlGetFloat(x, 0)));
}

As you can see, you can get data out of your row result via -> SqlGet*(). (SqlGetInt, SqlGetFloat, SqlGetString, SqlGetVector, SqlGetObject).

Once you are done with your sqlquery, simply let it go out of scope (exit the function, end the script, etc.). No further cleanup is necessary.

You CAN pass sqlqueries into other functions, and you can even pass them into closures DelayCommand(), AssignCommand(); but queries passed this way will NOT BE SAVED TO SAVEGAMES.

Any pending closures loaded from a savegame that reference a SQLQuery will fail.

For this reason, it is strongly discouraged for singleplayer modules to pass sqlquery variables into DelayCommand().

Transactions

You can use transactions in your code, but care needs to be taken to properly finalise them; otherwise, your database connection might become stuck in an aborted transaction. Specifically scripting/logic errors that result in "Too many instructions" are a pitfall to be aware of.

Limitations

  • Databases stored to the module savegame (accessed via SqlPrepareQueryObject(GetModule(), ...) should be kept to a reasonable size, as the data stored this way goes into the savegame.
    • A few megabytes is fine; but storing hundreds is going to give you grief.
  • Player-bound databases should be kept as minimal as possible, as the database is embedded into the player character file.