net.java.ao.db
Class HSQLDatabaseProvider

java.lang.Object
  net.java.ao.DatabaseProvider
      net.java.ao.db.HSQLDatabaseProvider

public class HSQLDatabaseProvider
extends DatabaseProvider

Author:

Daniel Spiewak

Nested Class Summary

Nested classes/interfaces inherited from class net.java.ao.DatabaseProvider

DatabaseProvider.SqlListener

Constructor Summary

HSQLDatabaseProvider(DisposableDataSource dataSource)

Method Summary

protected boolean	considerPrecision(DDLField field) Determines whether or not the database allows explicit precisions for the field in question.
protected String	convertTypeToString(DatabaseType<?> type) Converts the specified type into the database-specific DDL String value.
void	dispose() Frees any resources held by the database provider or delegate libraries (such as connection pools).
protected <T> T	executeInsertReturningKey(EntityManager manager, Connection conn, Class<T> pkType, String pkField, String sql, DBParam... params) Delegate method to execute an INSERT statement returning any auto-generated primary key values.
protected String	getDateFormat() Returns the database-specific TIMESTAMP text format as defined by the SimpleDateFormat syntax.
protected Set<String>	getReservedWords() Retrieves the set of all reserved words for the underlying database.
ResultSet	getTables(Connection conn) Returns a result set of all of the tables (and associated meta) in the database.
<T> T	insertReturningKey(EntityManager manager, Connection conn, Class<T> pkType, String pkField, boolean pkIdentity, String table, DBParam... params) Generates an INSERT statement to be used to create a new row in the database, returning the primary key value.
boolean	isCaseSensetive() Flag indicating whether or not the underlying database uses case-sensetive identifiers.
Object	parseValue(int type, String value) Parses the database-agnostic String value relevant to the specified SQL type in int form (as defined by Types and returns the Java value which corresponds.
protected String	renderAlterTableChangeColumnStatement(DDLTable table, DDLField oldField, DDLField field) Generates the database-specific DDL statement only for altering a table and changing a column.
protected String	renderAlterTableDropKey(DDLForeignKey key) Generates the database-specific DDL statement required to remove a foreign key from a table.
protected String	renderAutoIncrement() Generates the DDL fragment required to specify an INTEGER field as auto-incremented.
protected String	renderConstraintsForTable(DDLTable table) Renders the foreign key constraints in database-specific DDL for the table in question.
protected String	renderDropIndex(DDLIndex index) Generates the database-specific DDL statement required to drop an index.
protected String	renderFieldType(DDLField field) Renders the database-specific DDL type for the field in question.
protected String	renderOnUpdate(DDLField field) Renders the appropriate field suffix to allow for the OnUpdate functionality.
protected String	renderQueryLimit(Query query) Renders the LIMIT portion of the query in the database-specific SQL dialect.
protected String	renderQuerySelect(Query query, TableNameConverter converter, boolean count) Renders the SELECT portion of a given Query instance in the manner required by the database-specific SQL implementation.
protected String	renderUnique() Renders the UNIQUE constraint as defined by the database-specific DDL syntax.
protected String	renderValue(Object value) Renders the given Java instance in a database-specific way.

Methods inherited from class net.java.ao.DatabaseProvider

addSqlListener, executeUpdate, getConnection, getFunctionNameForField, getMaxIDLength, getSequences, getTriggerNameForField, handleBlob, handleUpdateError, isNumericType, onSql, preparedStatement, preparedStatement, preparedStatement, processID, processWhereClause, putBoolean, putNull, removeSqlListener, renderAction, renderAlterTableAddColumn, renderAlterTableAddKey, renderAlterTableChangeColumn, renderAlterTableDropColumn, renderAppend, renderCalendar, renderCreateIndex, renderDropFunctions, renderDropSequences, renderDropTable, renderDropTriggers, renderField, renderFieldPrecision, renderForeignKey, renderFunction, renderFunctionForField, renderFunctions, renderInsert, renderQuery, renderQueryGroupBy, renderQueryJoins, renderQueryOrderBy, renderQueryWhere, renderSequences, renderTable, renderTriggerForField, renderTriggers, setPostConnectionProperties, setQueryResultSetProperties, setQueryStatementProperties, shouldQuoteID

Methods inherited from class java.lang.Object

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

Constructor Detail

HSQLDatabaseProvider

public HSQLDatabaseProvider(DisposableDataSource dataSource)

Method Detail

insertReturningKey

public <T> T insertReturningKey(EntityManager manager,
                                Connection conn,
                                Class<T> pkType,
                                String pkField,
                                boolean pkIdentity,
                                String table,
                                DBParam... params)
                     throws SQLException

Description copied from class: DatabaseProvider

Generates an INSERT statement to be used to create a new row in the database, returning the primary key value. This method also invokes the delegate method, DatabaseProvider.executeInsertReturningKey(EntityManager, Connection, Class, String, String, DBParam...) passing the appropriate parameters and query. This method is required because some databases do not support the JDBC parameter RETURN_GENERATED_KEYS (such as HSQLDB and PostgreSQL). Also, some databases (such as MS SQL Server) require odd tricks to support explicit value passing to auto-generated fields. This method should take care of any extra queries or odd SQL generation required to implement both auto-generated primary key returning, as well as explicit primary key value definition.

Overriding implementations of this method should be sure to use the Connection instance passed to the method, not a new instance generated using the DatabaseProvider.getConnection() method. This is because this method is in fact a delegate invoked by EntityManager as part of the entity creation process and may be part of a transaction, a bulk creation or some more complicated operation. Both optimization and usage patterns on the API dictate that the specified connection instance be used. Implementations may assume that the given connection instance is never null.

The default implementation of this method should be sufficient for any fully compliant ANSI SQL database with a properly implemented JDBC driver. Note that this method should not not actually execute the SQL it generates, but pass it on to the DatabaseProvider.executeInsertReturningKey(EntityManager, Connection, Class, String, String, DBParam...) method, allowing for functional delegation and better extensibility. However, this method may execute any additional statements required to prepare for the INSERTion (as in the case of MS SQL Server which requires some config parameters to be set on the database itself prior to INSERT).

Overrides:

insertReturningKey in class DatabaseProvider

Parameters:

manager - The EntityManager which was used to dispatch the INSERT in question.

conn - The connection to be used in the eventual execution of the generated SQL statement.

pkType - The Java type of the primary key value. Can be used to perform a linear search for a specified primary key value in the params list. The return value of the method must be of the same type.

pkField - The database field which is the primary key for the table in question. Can be used to perform a linear search for a specified primary key value in the params list.

pkIdentity - Flag indicating whether or not the primary key field is auto-incremented by the database (IDENTITY field).

table - The name of the table into which the row is to be INSERTed.

params - A varargs array of parameters to be passed to the INSERT statement. This may include a specified value for the primary key.

Throws:

SQLException - If the INSERT fails in the delegate method, or if any additional statements fail with an exception.

See Also:

DatabaseProvider.executeInsertReturningKey(EntityManager, Connection, Class, String, String, DBParam...)

executeInsertReturningKey

protected <T> T executeInsertReturningKey(EntityManager manager,
                                          Connection conn,
                                          Class<T> pkType,
                                          String pkField,
                                          String sql,
                                          DBParam... params)
                               throws SQLException

Description copied from class: DatabaseProvider

Delegate method to execute an INSERT statement returning any auto-generated primary key values. This method is primarily designed to be called as a delegate from the DatabaseProvider.insertReturningKey(EntityManager, Connection, Class, String, boolean, String, DBParam...) method. The idea behind this method is to allow custom implementations to override this method to potentially execute other statements (such as getting the next value in a sequence) rather than the default implementaiton which uses the JDBC constant, RETURN_GENERATED_KEYS. Any database which has a fully-implemented JDBC driver should have no problems with the default implementation of this method.

Part of the design behind splitting insertReturningKey and executeInsertReturningKey is so that logic for generating the actual INSERT statement need not be duplicated throughout the code and in custom implementations providing trivial changes to the default algorithm. This method should avoid actually generating SQL if at all possible.

This method should iterate through the passed DBParam(s) to ensure that no primary key value was explicitly specified. If one was, it should be used in leiu of one which is auto-generated by the database. Also, it is this value which should be returned if specified, rather than the value which would have been generated or null. As such, this method should always return exactly the value of the primary key field in the row which was just inserted, regardless of what that value may be.

In cases where the database mechanism for getting the next primary key value is not thread safe, this method should be declared synchronized, or some thread synchronization technique employed. Unfortunately, it is not always possible to ensure that no other INSERT could (potentially) "steal" the expected value out from under the algorithm. Such scenarios are to be avoided when possible, but the algorithm need not take extremely escoteric concurrency cases into account. (see the HSQLDB provider for an example of such a less-than-thorough asynchronous algorithm)

IMPORTANT: The INSERT Statement must use the specified connection, rather than a new one retrieved from DatabaseProvider.getConnection() or equivalent. This is because the INSERT may be part of a bulk insertion, a transaction, or possibly another such operation. It is also important to note that this method should not close the connection. Doing so could cause the entity creation algorithm to fail at a higher level up the stack.

Overrides:

executeInsertReturningKey in class DatabaseProvider

Parameters:

manager - The EntityManager which was used to dispatch the INSERT in question.

conn - The database connection to use in executing the INSERT statement.

pkType - The Java class type of the primary key field (for use both in searching the params as well as performing value conversion of auto-generated DB values into proper Java instances).

pkField - The database field which is the primary key for the table in question. Can be used to perform a linear search for a specified primary key value in the params list.

params - A varargs array of parameters to be passed to the INSERT statement. This may include a specified value for the primary key.

Throws:

SQLException - If the INSERT fails in the delegate method, or if any additional statements fail with an exception.

See Also:

DatabaseProvider.insertReturningKey(EntityManager, Connection, Class, String, boolean, String, DBParam...)

parseValue

public Object parseValue(int type,
                         String value)

Description copied from class: DatabaseProvider

Parses the database-agnostic String value relevant to the specified SQL type in int form (as defined by Types and returns the Java value which corresponds. This method is completely database-agnostic, as are all of all of its delegate methods.

WARNING: This method is being considered for removal to another class (perhaps TypeManager?) as it is not a database-specific function and thus confuses the purpose of this class. Do not rely upon it heavily. (better yet, don't rely on it at all from external code. It's not designed to be part of the public API)

Overrides:

parseValue in class DatabaseProvider

Parameters:

type - The JDBC integer type of the database field against which to parse the value.

value - The database-agnostic String value to parse into a proper Java object with respect to the specified SQL type.

Returns:

A Java value which corresponds to the specified String.

getTables

public ResultSet getTables(Connection conn)
                    throws SQLException

Description copied from class: DatabaseProvider

Returns a result set of all of the tables (and associated meta) in the database. The fields of the result set must correspond with those specified in the DatabaseMetaData#getTables(String, String, String, String[]) method. In fact, the default implementation merely calls this method passing (null, null, "", null). For databases (such as PostgreSQL) where this is unsuitable, different parameters can be specified to the getTables method in the override, or an entirely new implementation written, as long as the result set corresponds in fields to the JDBC spec.

Overrides:

getTables in class DatabaseProvider

Parameters:

conn - The connection to use in retrieving the database tables.

Returns:

A result set of tables (and meta) corresponding in fields to the JDBC specification.

Throws:

SQLException

See Also:

DatabaseMetaData.getTables(String, String, String, String[])

dispose

public void dispose()

Description copied from class: DatabaseProvider

Frees any resources held by the database provider or delegate libraries (such as connection pools). This method should be once usage of the provider is complete to ensure that all connections are committed and closed.

Overrides:

dispose in class DatabaseProvider

renderQuerySelect

protected String renderQuerySelect(Query query,
                                   TableNameConverter converter,
                                   boolean count)

Description copied from class: DatabaseProvider

Renders the SELECT portion of a given Query instance in the manner required by the database-specific SQL implementation. Usually, this is as simple as "SELECT id FROM table" or "SELECT DISTINCT * FROM table". However, some databases require the limit and offset parameters to be specified as part of the SELECT clause. For example, on HSQLDB, a Query for the "id" field limited to 10 rows would render SELECT like this: SELECT TOP 10 id FROM table.

There is usually no need to call this method directly. Under normal operations it functions as a delegate for DatabaseProvider.renderQuery(Query, TableNameConverter, boolean).

Overrides:

renderQuerySelect in class DatabaseProvider

Parameters:

query - The Query instance from which to determine the SELECT properties.

converter - The name converter to allow conversion of the query entity interface into a proper table name.

count - Whether or not the query should be rendered as a SELECT COUNT(*).

Returns:

The database-specific SQL rendering of the SELECT portion of the query.

renderQueryLimit

protected String renderQueryLimit(Query query)

Description copied from class: DatabaseProvider

Renders the LIMIT portion of the query in the database-specific SQL dialect. There is wide variety in database implementations of this particular SQL clause. In fact, many database do not support it at all. If the database in question does not support LIMIT, this method should be overridden to return an empty String. For such databases, LIMIT should be implemented by overriding DatabaseProvider.setQueryResultSetProperties(ResultSet, Query) and DatabaseProvider.setQueryStatementProperties(Statement, Query).

An example return value: " LIMIT 10,2"

There is usually no need to call this method directly. Under normal operations it functions as a delegate for DatabaseProvider.renderQuery(Query, TableNameConverter, boolean).

Overrides:

renderQueryLimit in class DatabaseProvider

Parameters:

query - The Query instance from which to determine the LIMIT properties.

Returns:

The database-specific SQL rendering of the LIMIT portion of the query.

renderFieldType

protected String renderFieldType(DDLField field)

Description copied from class: DatabaseProvider

Renders the database-specific DDL type for the field in question. This method merely delegates to the DatabaseProvider.convertTypeToString(DatabaseType) method, passing the field type. Thus, it is rarely necessary (if ever) to override this method. It may be deprecated in a future release.

Overrides:

renderFieldType in class DatabaseProvider

Parameters:

field - The field which contains the type to be rendered.

Returns:

The database-specific type DDL rendering.

renderAutoIncrement

protected String renderAutoIncrement()

Description copied from class: DatabaseProvider

Generates the DDL fragment required to specify an INTEGER field as auto-incremented. For databases which do not support such flags (which is just about every database exception MySQL), "" is an acceptable return value. This method should never return null as it would cause the field rendering method to throw a NullPointerException.

Overrides:

renderAutoIncrement in class DatabaseProvider

getDateFormat

protected String getDateFormat()

Description copied from class: DatabaseProvider

Returns the database-specific TIMESTAMP text format as defined by the SimpleDateFormat syntax. This format should include the time down to the second (or even more precise, if allowed by the database). The default implementation returns the format for MySQL, which is: yyyy-MM-dd HH:mm:ss

Overrides:

getDateFormat in class DatabaseProvider

Returns:

The database-specific TIMESTAMP text format

renderOnUpdate

protected String renderOnUpdate(DDLField field)

Description copied from class: DatabaseProvider

Renders the appropriate field suffix to allow for the OnUpdate functionality. For most databases (read: all but MySQL) this will return an empty String. This is because few databases provide an implicit ON UPDATE syntax for fields. As such, most databases will be compelled to return an empty String and implement the functionality using triggers.

Overrides:

renderOnUpdate in class DatabaseProvider

Parameters:

field - The field for which the ON UPDATE clause should be rendered.

Returns:

The database-specific ON UPDATE field clause.

renderUnique

protected String renderUnique()

Description copied from class: DatabaseProvider

Renders the UNIQUE constraint as defined by the database-specific DDL syntax. This method is a delegate of other, more complex methods such as DatabaseProvider.renderField(DDLField). The default implementation just returns UNIQUE. Implementations may override this method to return an empty String if the database in question does not support the constraint.

Overrides:

renderUnique in class DatabaseProvider

Returns:

The database-specific rendering of UNIQUE.

renderConstraintsForTable

protected String renderConstraintsForTable(DDLTable table)

Description copied from class: DatabaseProvider

Renders the foreign key constraints in database-specific DDL for the table in question. Actually, this method only loops through the foreign keys and renders indentation and line-breaks. The actual rendering is done in a second delegate method.

Overrides:

renderConstraintsForTable in class DatabaseProvider

Parameters:

table - The database-agnostic DDL representation of the table in question.

Returns:

The String rendering of all of the foreign keys for the table.

See Also:

DatabaseProvider.renderForeignKey(DDLForeignKey)

convertTypeToString

protected String convertTypeToString(DatabaseType<?> type)

Description copied from class: DatabaseProvider

Converts the specified type into the database-specific DDL String value. By default, this delegates to the DatabaseType#getDefaultName() method. Subclass implementations should be sure to make a super call in order to ensure that both default naming and future special cases are handled appropriately.

Overrides:

convertTypeToString in class DatabaseProvider

Parameters:

type - The type instance to convert to a DDL string.

Returns:

The database-specific DDL representation of the type (e.g. "VARCHAR").

See Also:

DatabaseType.getDefaultName()

considerPrecision

protected boolean considerPrecision(DDLField field)

Description copied from class: DatabaseProvider

Determines whether or not the database allows explicit precisions for the field in question. This is to support databases such as Derby which do not support precisions for certain types. By default, this method returns true.

More often than not, all that is required for this determination is the type. As such, the method signature may change in a future release.

Overrides:

considerPrecision in class DatabaseProvider

Parameters:

field - The field for which precision should/shouldn't be rendered.

Returns:

true if precision should be rendered, otherwise false.

renderValue

protected String renderValue(Object value)

Description copied from class: DatabaseProvider

Renders the given Java instance in a database-specific way. This method handles special cases such as Calendar, Boolean (which is always rendered as 0/1), functions, null and numbers. All other values are rendered (by default) as 'value.toString()' (the String value enclosed within single quotes). Implementations are encouraged to override this method as necessary.

Overrides:

renderValue in class DatabaseProvider

Parameters:

value - The Java instance to be rendered as a database literal.

Returns:

The database-specific String rendering of the instance in question.

See Also:

DatabaseProvider.renderCalendar(Calendar), DatabaseProvider.renderFunction(DatabaseFunction)

renderAlterTableChangeColumnStatement

protected String renderAlterTableChangeColumnStatement(DDLTable table,
                                                       DDLField oldField,
                                                       DDLField field)

Description copied from class: DatabaseProvider

Generates the database-specific DDL statement only for altering a table and changing a column. This method must only generate a single statement as it does not need to concern itself with functions or triggers associated with the column. This method is only to be called as a delegate for the DatabaseProvider.renderAlterTableChangeColumn(DDLTable, DDLField, DDLField) method, for which it is a primary delegate. The default implementation of this method functions according to the MySQL specification.

Overrides:

renderAlterTableChangeColumnStatement in class DatabaseProvider

Parameters:

table - The table containing the column to change.

oldField - The old column definition.

field - The new column definition (defining the resultant DDL).

Returns:

A single DDL statement which is to be executed.

See Also:

DatabaseProvider.renderField(DDLField)

renderAlterTableDropKey

protected String renderAlterTableDropKey(DDLForeignKey key)

Description copied from class: DatabaseProvider

Generates the database-specific DDL statement required to remove a foreign key from a table. For databases which do not support such a statement, a warning should be printed to stderr and a null value returned. This method assumes that the DatabaseProvider.renderForeignKey(DDLForeignKey) method properly names the foreign key according to the DDLForeignKey.getFKName() method.

Overrides:

renderAlterTableDropKey in class DatabaseProvider

Parameters:

key - The foreign key to be removed. As this instance contains all necessary data (such as domestic table, field, etc), no additional parameters are required.

Returns:

A DDL statement to be executed, or null.

renderDropIndex

protected String renderDropIndex(DDLIndex index)

Description copied from class: DatabaseProvider

Generates the database-specific DDL statement required to drop an index. The syntax for this operation is highly standardized and thus it is unlikely this method will be overridden. If the database in question does not support indexes, a warning should be printed to stderr and null returned.

Overrides:

renderDropIndex in class DatabaseProvider

Parameters:

index - The index to drop. This single instance contains all of the data necessary to drop the index, thus no separate parameters (such as a DDLTable) are required.

Returns:

A DDL statement to be executed, or null.

getReservedWords

protected Set<String> getReservedWords()

Description copied from class: DatabaseProvider

Retrieves the set of all reserved words for the underlying database. The set returns should be speculative, meaning that it should include any possible reserved words, not just those for a particular version. As an implementation guideline, the Set instance returned from this method should guarentee O(1) lookup times, otherwise ORM performance will suffer greatly.

Specified by:

getReservedWords in class DatabaseProvider

Returns:

A set of upper case reserved words specific to the database.

isCaseSensetive

public boolean isCaseSensetive()

Description copied from class: DatabaseProvider

Flag indicating whether or not the underlying database uses case-sensetive identifiers. This specifically affects comparisons in the SchemaReader utility. The default value is true. Note that databases which support both case-sensetive and case-insensetive identifiers (like MySQL) should return true for better all-around compatibility.

Overrides:

isCaseSensetive in class DatabaseProvider

Returns:

boolean true if identifiers are case-sensetive, false otherwise.