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MUSHclient scripting

Description of MUSHclient world function: world.DatabaseGetField


Name DatabaseGetField
Type Method
Summary Returns a single field from an SQL database
Prototype VARIANT DatabaseGetField(BSTR Name, BSTR Sql);

View list of data type meanings

Description

This executes SQL on a database previously opened with DatabaseOpen.

It lets you obtain a single value more easily than doing a DatabasePrepare / DatabaseStep / DatabaseColumnValue / DatabaseFinalize in the cases where you just want to establish a single thing (eg. the count of spells in a table).

You need to supply the database id of an existing opened database, and the SQL statement to be executed.

You cannot call DatabaseGetField if you have called DatabasePrepare but not DatabaseFinalize, as a statement is currently being processed.

The function effectively does this:

DatabasePrepare (Name, Sql)

If unsuccessful, exit with null variant.

Otherwise:
DatabaseStep (Name)

If successful, and a row was returned, then:
result = DatabaseColumnValue (Name, 1)

DatabaseFinalize (Name)


If successful, then the value for the first column of the first row is the return value, otherwise the null variant (nil in Lua).


Note: Available in version 4.65 onwards.


Lua example
DatabaseOpen ("db", GetInfo (82), 1)

value = DatabaseGetField ("db", 
                          "SELECT value FROM control WHERE name = 'Version' ")

DatabaseClose ("db")
Lua notes
Returns nil on error.
Returns The contents of the column, as a string, long, double or empty variant.

Returns the null variant if there is an error, such as invalid database id, no current row, etc.
Introduced in version 4.65

See also ...

Function Description
DatabaseClose Closes an SQLite database
DatabaseError Returns an English string describing the most recent SQL error
DatabaseExec Executes SQL code against an SQLite database
DatabaseFinalize Finalizes (wraps up) a previously-prepared SQL statement
DatabaseOpen Opens an SQLite database
DatabasePrepare Prepares an SQL statement for execution

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