org.dspace.storage.rdbms

Class DatabaseUtils

java.lang.Object

org.dspace.storage.rdbms.DatabaseUtils

public class DatabaseUtils
extends Object

Utility class used to manage the Database. This class is used by the DatabaseManager to initialize/upgrade/migrate the Database. It can also be called via the commandline as necessary to get information about the database.

Currently, we use Flyway DB (http://flywaydb.org/) for database management.

Author:

Tim Donohue

See Also:

DatabaseManager

Constructor Summary

Constructors

Constructor and Description
DatabaseUtils()

Method Summary

Methods

Modifier and Type	Method and Description
static String	canonicalize(Connection connection, String dbIdentifier) Return the canonical name for a database identifier based on whether this database defaults to storing identifiers in uppercase or lowercase.
static void	checkReindexDiscovery(IndexingService indexer) Method to check whether we need to reindex in Discovery (i.e.
static void	executeSql(Connection connection, String sqlToExecute) Execute a block of SQL against the current database connection.
static boolean	getReindexDiscovery() Whether or not reindexing is required in Discovery.
static String	getSchemaName(Connection connection) Get the Database Schema Name in use by this Connection, so that it can be used to limit queries in other methods (e.g.
static void	main(String[] argv) Commandline tools for managing database changes, etc.
static boolean	sequenceExists(Connection connection, String sequenceName)
static void	setReindexDiscovery(boolean reindex) Whether or not to tell Discovery to reindex itself based on the updated database.
static boolean	tableColumnExists(Connection connection, String tableName, String columnName) Determine if a particular database column exists in our database
static boolean	tableExists(Connection connection, String tableName) Determine if a particular database table exists in our database
static boolean	tableExists(Connection connection, String tableName, boolean caseSensitive) Determine if a particular database table exists in our database
protected static void	updateDatabase(DataSource datasource, Connection connection) Ensures the current database is up-to-date with regards to the latest DSpace DB schema.
protected static void	updateDatabase(DataSource datasource, Connection connection, String targetVersion, boolean outOfOrder) Ensures the current database is up-to-date with regards to the latest DSpace DB schema.

Methods inherited from class java.lang.Object

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

Constructor Detail

DatabaseUtils

public DatabaseUtils()

Method Detail

main

public static void main(String[] argv)

Commandline tools for managing database changes, etc.

Parameters:

argv -

updateDatabase

protected static void updateDatabase(DataSource datasource,
                  Connection connection)
                              throws SQLException

Ensures the current database is up-to-date with regards to the latest DSpace DB schema. If the scheme is not up-to-date, then any necessary database migrations are performed.

FlywayDB (http://flywaydb.org/) is used to perform database migrations. If a Flyway DB migration fails it will be rolled back to the last successful migration, and any errors will be logged.

Parameters:

datasource - DataSource object (retrieved from DatabaseManager())

connection - Database connection

Throws:

SQLException - If database cannot be upgraded.

updateDatabase

protected static void updateDatabase(DataSource datasource,
                  Connection connection,
                  String targetVersion,
                  boolean outOfOrder)
                              throws SQLException

Ensures the current database is up-to-date with regards to the latest DSpace DB schema. If the scheme is not up-to-date, then any necessary database migrations are performed.

FlywayDB (http://flywaydb.org/) is used to perform database migrations. If a Flyway DB migration fails it will be rolled back to the last successful migration, and any errors will be logged.

Parameters:

datasource - DataSource object (retrieved from DatabaseManager())

connection - Database connection

targetVersion - If specified, only migrate the database to a particular *version* of DSpace. This is mostly just useful for testing. If null, the database is migrated to the latest version.

outOfOrder - If true, Flyway will run any lower version migrations that were previously "ignored". If false, Flyway will only run new migrations with a higher version number.

Throws:

SQLException - If database cannot be upgraded.

tableExists

public static boolean tableExists(Connection connection,
                  String tableName)

Determine if a particular database table exists in our database

Parameters:

connection - Current Database Connection

tableName - The name of the table

Returns:

true if table of that name exists, false otherwise

tableExists

public static boolean tableExists(Connection connection,
                  String tableName,
                  boolean caseSensitive)

Determine if a particular database table exists in our database

Parameters:

connection - Current Database Connection

tableName - The name of the table

caseSensitive - When "true", the case of the tableName will not be changed. When "false, the name may be uppercased or lowercased based on DB type.

Returns:

true if table of that name exists, false otherwise

tableColumnExists

public static boolean tableColumnExists(Connection connection,
                        String tableName,
                        String columnName)

Determine if a particular database column exists in our database

Parameters:

connection - Current Database Connection

tableName - The name of the table

columnName - The name of the column in the table

Returns:

true if column of that name exists, false otherwise

sequenceExists

public static boolean sequenceExists(Connection connection,
                     String sequenceName)

executeSql

public static void executeSql(Connection connection,
              String sqlToExecute)
                       throws SQLException

Execute a block of SQL against the current database connection.

The SQL is executed using the Flyway SQL parser.

Parameters:

connection - Current Database Connection

sqlToExecute - The actual SQL to execute as a String

Throws:

SQLException - If a database error occurs

getSchemaName

public static String getSchemaName(Connection connection)
                            throws SQLException

Get the Database Schema Name in use by this Connection, so that it can be used to limit queries in other methods (e.g. tableExists()).

NOTE: Once we upgrade to using Apache Commons DBCP / Pool version 2.0, this method WILL BE REMOVED in favor of java.sql.Connection's new "getSchema()" method. http://docs.oracle.com/javase/7/docs/api/java/sql/Connection.html#getSchema()

Parameters:

connection - Current Database Connection

Returns:

Schema name as a string, or "null" if cannot be determined or unspecified

Throws:

SQLException

canonicalize

public static String canonicalize(Connection connection,
                  String dbIdentifier)
                           throws SQLException

Return the canonical name for a database identifier based on whether this database defaults to storing identifiers in uppercase or lowercase.

Parameters:

connection - Current Database Connection

dbIdentifier - Identifier to canonicalize (may be a table name, column name, etc)

Returns:

The canonical name of the identifier.

Throws:

SQLException

setReindexDiscovery

public static void setReindexDiscovery(boolean reindex)

Whether or not to tell Discovery to reindex itself based on the updated database.

Whenever a DB migration occurs this is set to "true" to ensure the Discovery index is updated. When Discovery initializes it calls checkReindexDiscovery() to reindex if this flag is true.

Because the DB migration may be initialized by commandline or any one of the many DSpace webapps, setting this to "true" actually writes a temporary file which lets Solr know when reindex is needed.

Parameters:

reindex - true or false

getReindexDiscovery

public static boolean getReindexDiscovery()

Whether or not reindexing is required in Discovery.

Because the DB migration may be initialized by commandline or any one of the many DSpace webapps, this checks for the existence of a temporary file to know when Discovery/Solr needs reindexing.

Returns:

whether reindex flag is true/false

checkReindexDiscovery

public static void checkReindexDiscovery(IndexingService indexer)

Method to check whether we need to reindex in Discovery (i.e. Solr). If reindexing is necessary, it is performed. If not, nothing happens.

This method is called by Discovery whenever it initializes a connection to Solr.

Parameters:

indexer - The actual indexer to use to reindex Discovery, if needed

See Also:

SolrServiceImpl