Package org.hibernate.dialect

Class HSQLDialect

java.lang.Object
org.hibernate.dialect.Dialect
org.hibernate.dialect.HSQLDialect
public class HSQLDialect extends Dialect
An SQL dialect compatible with HSQLDB (HyperSQL).

Note this version supports HSQLDB version 1.8 and higher, only.

Enhancements to version 3.5.0 GA to provide basic support for both HSQLDB 1.8.x and 2.x Does not works with Hibernate 3.2 - 3.4 without alteration.

  • Constructor Details

    • HSQLDialect

      public HSQLDialect()

  • Method Details

    • getAddColumnString

      public String getAddColumnString()
      Description copied from class: Dialect
      The syntax used to add a column to a table (optional).
      Overrides:
      getAddColumnString in class Dialect
      Returns:
      The "add column" fragment.

    • supportsIdentityColumns

      public boolean supportsIdentityColumns()
      Description copied from class: Dialect
      Does this dialect support identity column key generation?
      Overrides:
      supportsIdentityColumns in class Dialect
      Returns:
      True if IDENTITY columns are supported; false otherwise.

    • getIdentityColumnString

      public String getIdentityColumnString()
      Description copied from class: Dialect
      The syntax used during DDL to define a column as being an IDENTITY.
      Overrides:
      getIdentityColumnString in class Dialect
      Returns:
      The appropriate DDL fragment.

    • getIdentitySelectString

      public String getIdentitySelectString()
      Description copied from class: Dialect
      Get the select command to use to retrieve the last generated IDENTITY value.
      Overrides:
      getIdentitySelectString in class Dialect
      Returns:
      The appropriate select command

    • getIdentityInsertString

      public String getIdentityInsertString()
      Description copied from class: Dialect
      The keyword used to insert a generated value into an identity column (or null). Need if the dialect does not support inserts that specify no column values.
      Overrides:
      getIdentityInsertString in class Dialect
      Returns:
      The appropriate keyword.

    • supportsLockTimeouts

      public boolean supportsLockTimeouts()
      Description copied from class: Dialect
      Informational metadata about whether this dialect is known to support specifying timeouts for requested lock acquisitions.
      Overrides:
      supportsLockTimeouts in class Dialect
      Returns:
      True is this dialect supports specifying lock timeouts.

    • getForUpdateString

      public String getForUpdateString()
      Description copied from class: Dialect
      Get the string to append to SELECT statements to acquire locks for this dialect.
      Overrides:
      getForUpdateString in class Dialect
      Returns:
      The appropriate FOR UPDATE clause string.

    • supportsUnique

      public boolean supportsUnique()
      Description copied from class: Dialect
      Does this dialect support the UNIQUE column syntax?
      Overrides:
      supportsUnique in class Dialect
      Returns:
      boolean

    • supportsLimit

      public boolean supportsLimit()
      Description copied from class: Dialect
      Does this dialect support some form of limiting query results via a SQL clause?
      Overrides:
      supportsLimit in class Dialect
      Returns:
      True if this dialect supports some form of LIMIT.

    • getLimitString

      public String getLimitString(String sql, boolean hasOffset)
      Description copied from class: Dialect
      Apply s limit clause to the query.

      Typically dialects utilize variable limit clauses when they support limits. Thus, when building the select command we do not actually need to know the limit or the offest since we will just be using placeholders.

      Here we do still pass along whether or not an offset was specified so that dialects not supporting offsets can generate proper exceptions. In general, dialects will override one or the other of this method and Dialect.getLimitString(String, int, int).

      Overrides:
      getLimitString in class Dialect
      Parameters:
      sql - The query to which to apply the limit.
      hasOffset - Is the query requesting an offset?
      Returns:
      the modified SQL

    • bindLimitParametersFirst

      public boolean bindLimitParametersFirst()
      Description copied from class: Dialect
      Does the LIMIT clause come at the start of the SELECT statement, rather than at the end?
      Overrides:
      bindLimitParametersFirst in class Dialect
      Returns:
      true if limit parameters should come before other parameters

    • supportsIfExistsAfterTableName

      public boolean supportsIfExistsAfterTableName()
      Overrides:
      supportsIfExistsAfterTableName in class Dialect

    • supportsColumnCheck

      public boolean supportsColumnCheck()
      Description copied from class: Dialect
      Does this dialect support column-level check constraints?
      Overrides:
      supportsColumnCheck in class Dialect
      Returns:
      True if column-level CHECK constraints are supported; false otherwise.

    • supportsSequences

      public boolean supportsSequences()
      Description copied from class: Dialect
      Does this dialect support sequences?
      Overrides:
      supportsSequences in class Dialect
      Returns:
      True if sequences supported; false otherwise.

    • supportsPooledSequences

      public boolean supportsPooledSequences()
      Description copied from class: Dialect
      Does this dialect support "pooled" sequences. Not aware of a better name for this. Essentially can we specify the initial and increment values?
      Overrides:
      supportsPooledSequences in class Dialect
      Returns:
      True if such "pooled" sequences are supported; false otherwise.
      See Also:

    • getCreateSequenceString

      protected String getCreateSequenceString(String sequenceName)
      Description copied from class: Dialect
      Typically dialects which support sequences can create a sequence with a single command. This is convenience form of Dialect.getCreateSequenceStrings(java.lang.String) to help facilitate that.

      Dialects which support sequences and can create a sequence in a single command need *only* override this method. Dialects which support sequences but require multiple commands to create a sequence should instead override Dialect.getCreateSequenceStrings(java.lang.String).

      Overrides:
      getCreateSequenceString in class Dialect
      Parameters:
      sequenceName - The name of the sequence
      Returns:
      The sequence creation command

    • getDropSequenceString

      protected String getDropSequenceString(String sequenceName)
      Description copied from class: Dialect
      Typically dialects which support sequences can drop a sequence with a single command. This is convenience form of Dialect.getDropSequenceStrings(java.lang.String) to help facilitate that.

      Dialects which support sequences and can drop a sequence in a single command need *only* override this method. Dialects which support sequences but require multiple commands to drop a sequence should instead override Dialect.getDropSequenceStrings(java.lang.String).

      Overrides:
      getDropSequenceString in class Dialect
      Parameters:
      sequenceName - The name of the sequence
      Returns:
      The sequence drop commands

    • getSelectSequenceNextValString

      public String getSelectSequenceNextValString(String sequenceName)
      Description copied from class: Dialect
      Generate the select expression fragment that will retrieve the next value of a sequence as part of another (typically DML) statement.

      This differs from Dialect.getSequenceNextValString(String) in that this should return an expression usable within another statement.

      Overrides:
      getSelectSequenceNextValString in class Dialect
      Parameters:
      sequenceName - the name of the sequence
      Returns:
      The "nextval" fragment.

    • getSequenceNextValString

      public String getSequenceNextValString(String sequenceName)
      Description copied from class: Dialect
      Generate the appropriate select statement to to retrieve the next value of a sequence.

      This should be a "stand alone" select statement.

      Overrides:
      getSequenceNextValString in class Dialect
      Parameters:
      sequenceName - the name of the sequence
      Returns:
      String The "nextval" select string.

    • getQuerySequencesString

      public String getQuerySequencesString()
      Description copied from class: Dialect
      Get the select command used retrieve the names of all sequences.
      Overrides:
      getQuerySequencesString in class Dialect
      Returns:
      The select command; or null if sequences are not supported.
      See Also:

    • getViolatedConstraintNameExtracter

      public ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter()
      Overrides:
      getViolatedConstraintNameExtracter in class Dialect

    • getSelectClauseNullString

      public String getSelectClauseNullString(int sqlType)
      Description copied from class: Dialect
      Given a Types type code, determine an appropriate null value to use in a select clause.

      One thing to consider here is that certain databases might require proper casting for the nulls here since the select here will be part of a UNION/UNION ALL.

      Overrides:
      getSelectClauseNullString in class Dialect
      Parameters:
      sqlType - The Types type code.
      Returns:
      The appropriate select clause value fragment.

    • supportsUnionAll

      public boolean supportsUnionAll()
      Description copied from class: Dialect
      Does this dialect support UNION ALL, which is generally a faster variant of UNION?
      Overrides:
      supportsUnionAll in class Dialect
      Returns:
      True if UNION ALL is supported; false otherwise.

    • supportsTemporaryTables

      public boolean supportsTemporaryTables()
      Does this dialect support temporary tables?
      Overrides:
      supportsTemporaryTables in class Dialect
      Returns:
      True if temp tables are supported; false otherwise.

    • generateTemporaryTableName

      public String generateTemporaryTableName(String baseTableName)
      With HSQLDB 2.0, the table name is qualified with MODULE to assist the drop statement (in-case there is a global name beginning with HT_)
      Overrides:
      generateTemporaryTableName in class Dialect
      Parameters:
      baseTableName - The table name from which to base the temp table name.
      Returns:
      The generated temp table name.

    • getCreateTemporaryTableString

      public String getCreateTemporaryTableString()
      Command used to create a temporary table.
      Overrides:
      getCreateTemporaryTableString in class Dialect
      Returns:
      The command used to create a temporary table.

    • getCreateTemporaryTablePostfix

      public String getCreateTemporaryTablePostfix()
      No fragment is needed if data is not needed beyond commit, otherwise should add "on commit preserve rows"
      Overrides:
      getCreateTemporaryTablePostfix in class Dialect
      Returns:
      Any required postfix.

    • getDropTemporaryTableString

      public String getDropTemporaryTableString()
      Command used to drop a temporary table.
      Overrides:
      getDropTemporaryTableString in class Dialect
      Returns:
      The command used to drop a temporary table.

    • performTemporaryTableDDLInIsolation

      public Boolean performTemporaryTableDDLInIsolation()
      Different behavior for GLOBAL TEMPORARY (1.8) and LOCAL TEMPORARY (2.0)

      Possible return values and their meanings:

      Overrides:
      performTemporaryTableDDLInIsolation in class Dialect
      Returns:
      see the result matrix above.

    • dropTemporaryTableAfterUse

      public boolean dropTemporaryTableAfterUse()
      Do we need to drop the temporary table after use? todo - clarify usage by Hibernate Version 1.8 GLOBAL TEMPORARY table definitions persist beyond the end of the session (by default, data is cleared at commit).

      Version 2.x LOCAL TEMPORARY table definitions do not persist beyond the end of the session (by default, data is cleared at commit).

      Overrides:
      dropTemporaryTableAfterUse in class Dialect
      Returns:
      True if the table should be dropped.

    • supportsCurrentTimestampSelection

      public boolean supportsCurrentTimestampSelection()
      HSQLDB 1.8.x requires CALL CURRENT_TIMESTAMP but this should not be treated as a callable statement. It is equivalent to "select current_timestamp from dual" in some databases. HSQLDB 2.0 also supports VALUES CURRENT_TIMESTAMP
      Overrides:
      supportsCurrentTimestampSelection in class Dialect
      Returns:
      True if the current timestamp can be retrieved; false otherwise.

    • isCurrentTimestampSelectStringCallable

      public boolean isCurrentTimestampSelectStringCallable()
      Should the value returned by getCurrentTimestampSelectString() be treated as callable. Typically this indicates that JDBC escape syntax is being used...

      CALL CURRENT_TIMESTAMP is used but this should not be treated as a callable statement.

      Overrides:
      isCurrentTimestampSelectStringCallable in class Dialect
      Returns:
      True if the getCurrentTimestampSelectString() return is callable; false otherwise.

    • getCurrentTimestampSelectString

      public String getCurrentTimestampSelectString()
      Retrieve the command used to retrieve the current timestamp from the database.
      Overrides:
      getCurrentTimestampSelectString in class Dialect
      Returns:
      The command.

    • getCurrentTimestampSQLFunctionName

      public String getCurrentTimestampSQLFunctionName()
      The name of the database-specific SQL function for retrieving the current timestamp.
      Overrides:
      getCurrentTimestampSQLFunctionName in class Dialect
      Returns:
      The function name.

    • getLockingStrategy

      public LockingStrategy getLockingStrategy(Lockable lockable, LockMode lockMode)
      For HSQLDB 2.0, this is a copy of the base class implementation. For HSQLDB 1.8, only READ_UNCOMMITTED is supported.
      Overrides:
      getLockingStrategy in class Dialect
      Parameters:
      lockable - The persister for the entity to be locked.
      lockMode - The type of lock to be acquired.
      Returns:
      The appropriate locking strategy.
      Since:
      3.2

    • supportsCommentOn

      public boolean supportsCommentOn()
      Overrides:
      supportsCommentOn in class Dialect

    • supportsEmptyInList

      public boolean supportsEmptyInList()
      Description copied from class: Dialect
      Does this dialect support empty IN lists?

      For example, is [where XYZ in ()] a supported construct?

      Overrides:
      supportsEmptyInList in class Dialect
      Returns:
      True if empty in lists are supported; false otherwise.

    • requiresCastingOfParametersInSelectClause

      public boolean requiresCastingOfParametersInSelectClause()
      todo - needs usage clarification If the SELECT statement is always part of a UNION, then the type of parameter is resolved by v. 2.0, but not v. 1.8 (assuming the other SELECT in the UNION has a column reference in the same position and can be type-resolved). On the other hand if the SELECT statement is isolated, all versions of HSQLDB require casting for "select ? from .." to work.
      Overrides:
      requiresCastingOfParametersInSelectClause in class Dialect
      Returns:
      True if select clause parameter must be cast()ed
      Since:
      3.2

    • doesReadCommittedCauseWritersToBlockReaders

      public boolean doesReadCommittedCauseWritersToBlockReaders()
      For the underlying database, is READ_COMMITTED isolation implemented by forcing readers to wait for write locks to be released?
      Overrides:
      doesReadCommittedCauseWritersToBlockReaders in class Dialect
      Returns:
      True if writers block readers to achieve READ_COMMITTED; false otherwise.

    • doesRepeatableReadCauseReadersToBlockWriters

      public boolean doesRepeatableReadCauseReadersToBlockWriters()
      For the underlying database, is REPEATABLE_READ isolation implemented by forcing writers to wait for read locks to be released?
      Overrides:
      doesRepeatableReadCauseReadersToBlockWriters in class Dialect
      Returns:
      True if readers block writers to achieve REPEATABLE_READ; false otherwise.

    • supportsLobValueChangePropogation

      public boolean supportsLobValueChangePropogation()
      Description copied from class: Dialect
      Does the dialect support propagating changes to LOB values back to the database? Talking about mutating the internal value of the locator as opposed to supplying a new locator instance...

      For BLOBs, the internal value might be changed by: Blob.setBinaryStream(long), Blob.setBytes(long, byte[]), Blob.setBytes(long, byte[], int, int), or Blob.truncate(long).

      For CLOBs, the internal value might be changed by: Clob.setAsciiStream(long), Clob.setCharacterStream(long), Clob.setString(long, String), Clob.setString(long, String, int, int), or Clob.truncate(long).

      NOTE : I do not know the correct answer currently for databases which (1) are not part of the cruise control process or (2) do not Dialect.supportsExpectedLobUsagePattern().

      Overrides:
      supportsLobValueChangePropogation in class Dialect
      Returns:
      True if the changes are propagated back to the database; false otherwise.

    • toBooleanValueString

      public String toBooleanValueString(boolean bool)
      Description copied from class: Dialect
      The SQL literal value to which this database maps boolean values.
      Overrides:
      toBooleanValueString in class Dialect
      Parameters:
      bool - The boolean value
      Returns:
      The appropriate SQL literal.

    • supportsTupleDistinctCounts

      public boolean supportsTupleDistinctCounts()
      Description copied from class: Dialect
      Does this dialect support `count(distinct a,b)`?
      Overrides:
      supportsTupleDistinctCounts in class Dialect
      Returns:
      True if the database supports counting disintct tuples; false otherwise.