Package astra.util

Class DB

java.lang.Object

astra.core.Module

astra.util.DB

public class DB
extends Module

This class implements support for Database Acccess via JDBC.

To use this class, you must also have the correct JDBC driver jar, and this must be installed on the project classpath.

This is an early release and so its functionality may change, but will definitely be extended in future releases.

Example Usage:

module DB db;

rule +!main(list args) {
db.installDriver("org.sqlite.JDBC");
db.getConnection("jdbc:sqlite:test.db", object<java.sql.Connection> connection);
if (db.tableExists(connection, "users")) {
db.rawUpdateQuery(connection, "DROP TABLE users");
}
db.rawUpdateQuery(connection, "CREATE TABLE users (id INT PRIMARY KEY, username CHAR(50) NOT NULL, password CHAR(50) NOT NULL, email CHAR(50))");
db.rawUpdateQuery(connection, "INSERT INTO users (username, password, email) VALUES('user', 'pass', 'user@mail.com')");
db.rawSelectQuery(connection, "SELECT * FROM users", list results);
forall( list row : results) {
C.println("row: " + row);
}
db.close(connection);
}

Author:

Rem Collier

Nested Class Summary

Nested classes/interfaces inherited from class astra.core.Module

Module.ACTION, Module.EVENT, Module.FORMULA, Module.SENSOR, Module.SUPPRESS_NOTIFICATIONS, Module.TERM

Field Summary

Fields inherited from class astra.core.Module

agent

Constructor Summary

Constructors

Constructor	Description
DB()

Method Summary

Modifier and Type	Method	Description
boolean	close(Connection connection)	Action to close an existing SQL Connection
boolean	get(Connection connection, SQLQuery query, ActionParam<ListTerm> results)	Action that executes a select query on the database.
boolean	getConnection(String connectionString, ActionParam<Connection> connection)	Action to create a connection to a database.
SQLQuery	insert(String table, ListTerm fields, ListTerm values)	Term that creates a SELECT query of the form: INSERT INTO table VALUES (wf1=wv1, wf2=wv2)
boolean	installDriver(String driver)	Action that installs a JDBC driver.
boolean	rawSelectQuery(Connection connection, String sql, ActionParam<ListTerm> results)	Action that executes a basic select query on a connection.
boolean	rawUpdateQuery(Connection connection, String sql)	Action to execute a basic SQL Query.
SQLQuery	select(String table)	Term that creates a SELECT query of the form: SELECT * FROM table
SQLQuery	select(String table, ListTerm fields)	Term that creates a SELECT query of the form: SELECT listitem1, listitem2, ...
SQLQuery	select(String table, ListTerm where_fields, ListTerm where_values)	Term that creates a SELECT query of the form: SELECT * FROM table WHERE wf1=wv1 AND wf2=wv2 AND ...
SQLQuery	select(String table, ListTerm fields, ListTerm where_fields, ListTerm where_values)	Term that creates a SELECT query of the form: SELECT listitem1, listitem2, ...
SQLQuery	select(String table, String field)	Term that creates a SELECT query of the form: SELECT field FROM table
Formula	tableExists(Connection connection, String table)	Formula that checks if the provided table exists.
boolean	update(Connection connection, SQLQuery query)	Action that executes an update query on the database.
boolean	where(SQLQuery query, ListTerm fields, ListTerm values)	Action that allows you to add multiple where constrains in a single step.
boolean	where(SQLQuery query, String field, boolean value)	Action to add a where constrain for a boolean value
boolean	where(SQLQuery query, String field, char value)	Action to add a where constrain for a char value
boolean	where(SQLQuery query, String field, double value)	Action to add a where constrain for a double value
boolean	where(SQLQuery query, String field, float value)	Action to add a where constrain for a float value
boolean	where(SQLQuery query, String field, int value)	Action to add a where constrain for an int value
boolean	where(SQLQuery query, String field, long value)	Action to add a where constrain for a long value
boolean	where(SQLQuery query, String field, Object value)	Action to add a where constrain for an object
boolean	where(SQLQuery query, String field, String value)	Action to add a where constrain for a string value

Methods inherited from class astra.core.Module

inline, setAgent

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DB

public DB()

Method Detail

installDriver

public boolean installDriver(String driver)

Action that installs a JDBC driver.

The parameter is the fully qualified class name of the JDBC Driver

Parameters:

driver - a qualified class name for a driver

Returns:

true if the action succeeds, false otherwise

tableExists

public Formula tableExists(Connection connection,
                           String table)

Formula that checks if the provided table exists.

Parameters:

connection - a SQL Connection

table - the name of the table

Returns:

the formula TRUE if the table exists, the formula FALSE otherwise

getConnection

public boolean getConnection(String connectionString,
                             ActionParam<Connection> connection)

Action to create a connection to a database.

Parameters:

connectionString - the connection string

connection - a reference to an SQL Collection object.

Returns:

true if the action succeeds, false otherwise

close

public boolean close(Connection connection)

Action to close an existing SQL Connection

Parameters:

connection - the SQL connection

Returns:

true if the action succeeds, false otherwise

rawUpdateQuery

public boolean rawUpdateQuery(Connection connection,
                              String sql)

Action to execute a basic SQL Query.

This action is considered raw because it takes an SQL statement in string form as the input.

Parameters:

connection - and SQL connection

sql - the SQL update query

Returns:

true if the action succeeds, false otherwise

rawSelectQuery

public boolean rawSelectQuery(Connection connection,
                              String sql,
                              ActionParam<ListTerm> results)

Action that executes a basic select query on a connection.

This action is considered raw because it takes an SQL statement in string form as the input.

Parameters:

connection - a SQL connection

sql - the SQL Query

results - a list that contains the results of the query (list of list)

Returns:

true if the action succeeds, false otherwise

where

public boolean where(SQLQuery query,
                     String field,
                     String value)

Action to add a where constrain for a string value

Parameters:

query - the Query object

field - the field name

value - the value

Returns:

true if the action succeeds, false otherwise

where

public boolean where(SQLQuery query,
                     String field,
                     int value)

Action to add a where constrain for an int value

Parameters:

query - the Query object

field - the field name

value - the value

Returns:

true if the action succeeds, false otherwise

where

public boolean where(SQLQuery query,
                     String field,
                     long value)

Action to add a where constrain for a long value

Parameters:

query - the Query object

field - the field name

value - the value

Returns:

true if the action succeeds, false otherwise

where

public boolean where(SQLQuery query,
                     String field,
                     float value)

Action to add a where constrain for a float value

Parameters:

query - the Query object

field - the field name

value - the value

Returns:

true if the action succeeds, false otherwise

where

public boolean where(SQLQuery query,
                     String field,
                     double value)

Action to add a where constrain for a double value

Parameters:

query - the Query object

field - the field name

value - the value

Returns:

true if the action succeeds, false otherwise

where

public boolean where(SQLQuery query,
                     String field,
                     boolean value)

Action to add a where constrain for a boolean value

Parameters:

query - the Query object

field - the field name

value - the value

Returns:

true if the action succeeds, false otherwise

where

public boolean where(SQLQuery query,
                     String field,
                     char value)

Action to add a where constrain for a char value

Parameters:

query - the Query object

field - the field name

value - the value

Returns:

true if the action succeeds, false otherwise

where

public boolean where(SQLQuery query,
                     String field,
                     Object value)

Action to add a where constrain for an object

Parameters:

query - the Query object

field - the field name

value - the value

Returns:

true if the action succeeds, false otherwise

where

public boolean where(SQLQuery query,
                     ListTerm fields,
                     ListTerm values)

Action that allows you to add multiple where constrains in a single step.

The number of fields and values should match.

All fields should be of type string

Values should not be lists

Parameters:

query - the Query object

fields - a list of field names (strings)

values - a list of values

Returns:

true if the action succeeds, false otherwise

select

public SQLQuery select(String table)

Term that creates a SELECT query of the form: SELECT * FROM table

Parameters:

table - the name of the table

Returns:

a SQLQuery instance

select

public SQLQuery select(String table,
                       String field)

Term that creates a SELECT query of the form: SELECT field FROM table

Parameters:

table - the name of the table

field - the field name

Returns:

a SQLQuery instance

select

public SQLQuery select(String table,
                       ListTerm fields)

Term that creates a SELECT query of the form: SELECT listitem1, listitem2, ... FROM table

Parameters:

table - the name of the table

fields - a list of field names

Returns:

a SQLQuery instance

select

public SQLQuery select(String table,
                       ListTerm where_fields,
                       ListTerm where_values)

Term that creates a SELECT query of the form:
SELECT * FROM table WHERE wf1=wv1 AND wf2=wv2 AND ...

Parameters:

table - the name of the table

where_fields - a list of field names for the where clause

where_values - a list of values for the where clause

Returns:

a SQLQuery instance

select

public SQLQuery select(String table,
                       ListTerm fields,
                       ListTerm where_fields,
                       ListTerm where_values)

Term that creates a SELECT query of the form:
SELECT listitem1, listitem2, ... FROM table WHERE wf1=wv1 AND wf2=wv2 AND ...

Parameters:

table - the name of the table

fields - a list of field names

where_fields - a list of field names for the where clause

where_values - a list of values for the where clause

Returns:

a SQLQuery instance

get

public boolean get(Connection connection,
                   SQLQuery query,
                   ActionParam<ListTerm> results)

Action that executes a select query on the database.

Parameters:

connection - the database connection

query - a Query object

results - a container for the results

Returns:

true if the action succeeds, false otherwise

insert

public SQLQuery insert(String table,
                       ListTerm fields,
                       ListTerm values)

Term that creates a SELECT query of the form:
INSERT INTO table VALUES (wf1=wv1, wf2=wv2)

Parameters:

table - the name of the table

fields - a list of field names for the where clause

values - a list of values for the where clause

Returns:

true if the action succeeds, false otherwise

update

public boolean update(Connection connection,
                      SQLQuery query)

Action that executes an update query on the database.

Parameters:

connection - the database connection

query - a Query object

Returns:

true if the action succeeds, false otherwise