====== Database Connector ======

**''public class DatabaseConnector''**\\
**''extends java.lang.Object''**\\
\\
Class for database connection. Database connection is established with PostgreSQL JDBC Driver, a Java library that allows Java programs to connect to a PostgreSQL database.\\

Functions:
  * Read schemas relations, and foreign keys from database
  * Add/Edit/Delete schema (and relation)
  * Get and add remote database connection information (only for remote database schema)
  * Evaluate SQL query (only for remote database schema)
  * Validate and add user
  * Initialize required tables in installation process (for localhost application version)
Deprecated functions:
  * Read foreign keys, finite domain constraints, TC statements, and queries from database
  * Add/Edit/Delete foreign keys, finite domain constraints, TC statements, and queries in database
  * Copy and restore schema from/to database

===== Class Attributes  =====
<code java>
private java.sql.Connection connection
</code>
===== Class Constructors =====
==== DatabaseConnector ====
<code java>
public DatabaseConnector()
                  throws java.sql.SQLException
</code>
Constructor (for test only).\\

**Throws:**
  * java.sql.SQLException

----
==== DatabaseConnector ====
<code java>
public DatabaseConnector(boolean webApp,
                 java.lang.String appPath)
                  throws java.sql.SQLException,
                         java.lang.ClassNotFoundException,
                         java.io.IOException
</code>
Constructor.\\

//Called in [[magik-demo:developer:magik-business-logic#index.jsp|index.jsp]].//

**Parameters:**
  * webApp - true if web application, false otherwise
  * appPath - application path

**Throws:**
  * java.sql.SQLException
  * java.lang.ClassNotFoundException
  * java.io.IOException

----
==== DatabaseConnector ====
<code java>
public DatabaseConnector(java.lang.String dbUrl,
                 java.lang.String dbUsername,
                 java.lang.String dbPassword)
                  throws java.sql.SQLException,
                         java.lang.ClassNotFoundException
</code>
Constructor.

//Called by://
  * //[[magik-demo:developer:class:sessioncontrol#addDbConnection|addDbConnection(String, String, String) : void - it.unibz.inf.magik.web.SessionControl]]//
  * //[[magik-demo:developer:class:sessioncontrol#readDBSchemas|readDBSchemas(boolean) : void - it.unibz.inf.magik.web.SessionControl]]//
  * //[[magik-demo:developer:class:sessioncontrol#printQueryResultHTML|printQueryResultHTML(SessionSchema, int) : String - it.unibz.inf.magik.web.SessionControl]]//
**Parameters:**
  * dbUrl - database url
  * dbUsername - database username
  * dbPassword - database password
**Throws:**
  * java.sql.SQLException
  * java.lang.ClassNotFoundException

===== Class Methods =====
==== getSchemaType====
<code java>
private java.lang.String getSchemaType(boolean localSchema)
</code>
Get schema type.

**Parameters:**
  * localSchema - true if virtual schema, false if remote schema
**Returns:**
  * String "local" if localSchema is true, "remote" otherwise
 

----

==== getSchemas====
<code java>
public java.util.ArrayList<java.lang.String> getSchemas(boolean localSchema,
                                               java.lang.String username)
                                                 throws java.sql.SQLException
</code>
Get list of schemas.

//Called by: [[magik-demo:developer:class:sessioncontrol#readDBSchemas|readDBSchemas(boolean) : void - it.unibz.inf.magik.web.SessionControl]]//

**Parameters:**
  * localSchema - true if virtual schema, false if remote schema
  * username -
**Returns:**
  * list of schema names
**Throws:**
  * java.sql.SQLException

----
==== getDbSchemas====
<code java>
public java.util.ArrayList<java.lang.String> getDbSchemas()
                                                   throws java.sql.SQLException
</code>
Get list of schemas from remote database connection.

//Called by: [[magik-demo:developer:class:sessioncontrol#addDbConnection|addDbConnection(String, String, String) : void - it.unibz.inf.magik.web.SessionControl]]//

**Returns:**
  * list of schema names
**Throws:**
  * java.sql.SQLException

----
==== getSchema====
<code java>
public Schema getSchema(java.lang.String schemaName,
               boolean localSchema)
</code>
Initialize new schema.

//Called by: [[magik-demo:developer:class:sessioncontrol#readDBSchemas|readDBSchemas(boolean) : void - it.unibz.inf.magik.web.SessionControl]]//

**Parameters:**
  * schemaName - schema name
  * localSchema - true if virtual schema, false if remote schema
**Returns:**
  * Schema new schema

----
==== readRelation====
<code java>
public java.util.ArrayList<Relation> readRelation(java.lang.String schema,
                                         java.lang.String username)
                                           throws java.sql.SQLException
</code>
Read relations from virtual schema (in local database).

//Called by: [[magik-demo:developer:class:sessioncontrol#readDBSchemas|readDBSchemas(boolean) : void - it.unibz.inf.magik.web.SessionControl]]//

**Parameters:**
  * schema - schema name
  * username -
**Returns:**
  * arrRel list of relations
**Throws:**
  * java.sql.SQLException

----
==== readRelation====
<code java>
public java.util.ArrayList<Relation> readRelation(java.lang.String schemaName)
                                           throws java.sql.SQLException
</code>
Read relations from remote database schema.

//Called by: [[magik-demo:developer:class:sessioncontrol#readDBSchemas|readDBSchemas(boolean) : void - it.unibz.inf.magik.web.SessionControl]]//

**Parameters:**
  * schemaName - schema name
**Returns:**
  * arrRel list of relations
**Throws:**
  * java.sql.SQLException

----
==== readForeignKeys====
<code java>
public java.util.ArrayList<ForeignKey> readForeignKeys(java.lang.String schemaNm,
                                              Schema schema,
                                              java.lang.String username)
                                                throws java.sql.SQLException
</code>
Read database schema foreign key.

//Called by: [[magik-demo:developer:class:sessioncontrol#readFK|readFK() : ArrayList - it.unibz.inf.magik.web.SessionControl]]//

**Parameters:**
  * schemaNm - schema name
  * schema -
  * username -
**Returns:**
  * list of foreign keys
**Throws:**
  * java.sql.SQLException

----
==== addRelation====
<code java>
private void addRelation(Relation r,
               java.lang.String schema,
               java.lang.String username)
                  throws java.sql.SQLException
</code>
Add relation to the schema.

//Called by: [[#addSchema|addSchema(Schema, String) : void - it.unibz.inf.magik.db.DatabaseConnector]]//

**Parameters:**
  * r - relation to be added
  * schema -
  * username -
**Throws:**
  * java.sql.SQLException

----
==== addSchema====
<code java>
public void addSchema(Schema schema,
             java.lang.String username)
               throws java.sql.SQLException
</code>
Add schema to database.

//Called by://
  * //[[magik-demo:developer:class:sessioncontrol#addSchema|addSchema(SessionSchema, String) : void - it.unibz.inf.magik.web.SessionControl]]//
  * //[[#updateSchema|updateSchema(Schema, String, String) : void - it.unibz.inf.magik.db.DatabaseConnector]]//

**Parameters:**
  * schema -
  * username -
**Throws:**
  * java.sql.SQLException

----
==== deleteSchema====
<code java>
public void deleteSchema(Schema schema,
                java.lang.String username)
                  throws java.sql.SQLException
</code>
Delete schema from database.

//Called by://
  * //[[magik-demo:developer:class:sessioncontrol#deleteSchema|deleteSchema(String) : void - it.unibz.inf.magik.web.SessionControl]]//
  * //[[#updateSchema|updateSchema(Schema, String, String) : void - it.unibz.inf.magik.db.DatabaseConnector]]//

**Parameters:**
  * schema -
  * username -
**Throws:**
  * java.sql.SQLException

----
==== updateSchema====
<code java>
public void updateSchema(Schema schema,
                java.lang.String newSchemaName,
                java.lang.String username)
                  throws java.sql.SQLException
</code>
Update schema in database.

//Called by: [[magik-demo:developer:class:sessioncontrol#updateSchema|updateSchema(Schema, String) : void - it.unibz.inf.magik.web.SessionControl]]//

**Parameters:**
  * schema -
  * newSchemaName -
  * username -
**Throws:**
  * java.sql.SQLException

----
==== getDbUrl====
<code java>
public java.lang.String getDbUrl(java.lang.String schema,
                        java.lang.String username)
                          throws java.sql.SQLException
</code>
Get string of database url information (for remote database schema) from database.

//Called by://
  * //[[magik-demo:developer:class:sessioncontrol#readDBSchemas|readDBSchemas(boolean) : void - it.unibz.inf.magik.web.SessionControl]]//
  * //[[magik-demo:developer:class:sessioncontrol#printQueryResultHTML|printQueryResultHTML(SessionSchema, int) : String - it.unibz.inf.magik.web.SessionControl]]//

**Parameters:**
  * schema -
  * username -
**Throws:**
  * java.sql.SQLException

----
==== getDbUser====
<code java>
public java.lang.String getDbUser(java.lang.String schema,
                         java.lang.String username)
                           throws java.sql.SQLException
</code>
Get string of database username information (for remote database schema) from database.

//Called by://
  * //[[magik-demo:developer:class:sessioncontrol#readDBSchemas|readDBSchemas(boolean) : void - it.unibz.inf.magik.web.SessionControl]]//
  * //[[magik-demo:developer:class:sessioncontrol#printQueryResultHTML|printQueryResultHTML(SessionSchema, int) : String - it.unibz.inf.magik.web.SessionControl]]//
**Parameters:**
  * schema -
  * username -
**Throws:**
  * java.sql.SQLException

----
==== getDbPassword====
<code java>
public java.lang.String getDbPassword(java.lang.String schema,
                             java.lang.String username)
                               throws java.sql.SQLException
</code>
Get string of database password information (for remote database schema) from database.

//Called by://
  * //[[magik-demo:developer:class:sessioncontrol#readDBSchemas|readDBSchemas(boolean) : void - it.unibz.inf.magik.web.SessionControl]]//
  * //[[magik-demo:developer:class:sessioncontrol#printQueryResultHTML|printQueryResultHTML(SessionSchema, int) : String - it.unibz.inf.magik.web.SessionControl]]//
**Parameters:**
  * schema -
  * username -
**Throws:**
  * java.sql.SQLException

----
==== addDbConnection====
<code java>
public void addDbConnection(java.lang.String schemaName,
                   java.lang.String username,
                   java.lang.String dbUrl,
                   java.lang.String dbUser,
                   java.lang.String dbPassword)
                     throws java.sql.SQLException
</code>
Add remote database connection details to local database.

//Called by: //[[magik-demo:developer:class:sessioncontrol#addDbConnection|addDbConnection(String, String, String) : void - it.unibz.inf.magik.web.SessionControl]]////

**Parameters:**
  * schemaName -
  * username -
  * dbUrl - database url
  * dbUser - database username
  * dbPassword - database password
**Throws:**
  * java.sql.SQLException

----
==== evaluateQuery====
<code java>
public java.util.ArrayList<java.lang.String> evaluateQuery(Query q,
                                                  java.lang.String schemaName)
                                                    throws java.sql.SQLException
</code>
Evaluate SQL query.

//Called by: [[magik-demo:developer:class:sessioncontrol#printQueryResultHTML|printQueryResultHTML(SessionSchema, int) : String - it.unibz.inf.magik.web.SessionControl]]//

**Parameters:**
  * q - SQL query
  * schemaName - schema name
**Throws:**
  * java.sql.SQLException

----


==== installation====
<code java>
public void installation()
                  throws java.sql.SQLException
</code>
Initialize required tables in installation process (for localhost application version).\\

**Throws:**
  * java.sql.SQLException

----
==== closeConnection====
<code java>
public void closeConnection()
                     throws java.sql.SQLException
</code>
Close database connection.

**Throws:**
  * java.sql.SQLException

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