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java.lang.Object org.hibernate.dialect.Dialect org.hibernate.dialect.H2Dialect
public class H2Dialect
A dialect compatible with the H2 database.
Field Summary |
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Fields inherited from class org.hibernate.dialect.Dialect |
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CLOSED_QUOTE, DEFAULT_BATCH_SIZE, NO_BATCH, QUOTE |
Constructor Summary | |
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H2Dialect()
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Method Summary | |
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boolean |
bindLimitParametersFirst()
Does the LIMIT clause come at the start of the SELECT statement, rather than at the end? |
boolean |
bindLimitParametersInReverseOrder()
ANSI SQL defines the LIMIT clause to be in the form LIMIT offset, limit. |
boolean |
doesReadCommittedCauseWritersToBlockReaders()
For the underlying database, is READ_COMMITTED isolation implemented by forcing readers to wait for write locks to be released? |
boolean |
dropTemporaryTableAfterUse()
Do we need to drop the temporary table after use? |
String |
getAddColumnString()
The syntax used to add a column to a table (optional). |
String |
getCreateSequenceString(String sequenceName)
Typically dialects which support sequences can create a sequence with a single command. |
String |
getCreateTemporaryTableString()
Command used to create a temporary table. |
String |
getCurrentTimestampSelectString()
Retrieve the command used to retrieve the current timestamp from the database. |
String |
getDropSequenceString(String sequenceName)
Typically dialects which support sequences can drop a sequence with a single command. |
String |
getForUpdateString()
Get the string to append to SELECT statements to acquire locks for this dialect. |
String |
getIdentityColumnString()
The syntax used during DDL to define a column as being an IDENTITY. |
String |
getIdentityInsertString()
The keyword used to insert a generated value into an identity column (or null). |
String |
getIdentitySelectString()
Get the select command to use to retrieve the last generated IDENTITY value. |
String |
getLimitString(String sql,
boolean hasOffset)
Apply s limit clause to the query. |
String |
getQuerySequencesString()
Get the select command used retrieve the names of all sequences. |
String |
getSelectSequenceNextValString(String sequenceName)
Generate the select expression fragment that will retrieve the next value of a sequence as part of another (typically DML) statement. |
String |
getSequenceNextValString(String sequenceName)
Generate the appropriate select statement to to retrieve the next value of a sequence. |
ViolatedConstraintNameExtracter |
getViolatedConstraintNameExtracter()
|
boolean |
isCurrentTimestampSelectStringCallable()
Should the value returned by Dialect.getCurrentTimestampSelectString()
be treated as callable. |
Boolean |
performTemporaryTableDDLInIsolation()
Does the dialect require that temporary table DDL statements occur in isolation from other statements? This would be the case if the creation would cause any current transaction to get committed implicitly. |
boolean |
supportsCurrentTimestampSelection()
Does this dialect support a way to retrieve the database's current timestamp value? |
boolean |
supportsIdentityColumns()
Does this dialect support identity column key generation? |
boolean |
supportsIfExistsAfterTableName()
|
boolean |
supportsLimit()
Does this dialect support some form of limiting query results via a SQL clause? |
boolean |
supportsLobValueChangePropogation()
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... |
boolean |
supportsPooledSequences()
Does this dialect support "pooled" sequences. |
boolean |
supportsSequences()
Does this dialect support sequences? |
boolean |
supportsTemporaryTables()
Does this dialect support temporary tables? |
boolean |
supportsTupleDistinctCounts()
Does this dialect support `count(distinct a,b)`? |
boolean |
supportsUnionAll()
Does this dialect support UNION ALL, which is generally a faster variant of UNION? |
boolean |
supportsUnique()
Does this dialect support the UNIQUE column syntax? |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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public H2Dialect()
Method Detail |
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public String getAddColumnString()
Dialect
getAddColumnString
in class Dialect
public boolean supportsIdentityColumns()
Dialect
supportsIdentityColumns
in class Dialect
public String getIdentityColumnString()
Dialect
getIdentityColumnString
in class Dialect
public String getIdentitySelectString()
Dialect
getIdentitySelectString
in class Dialect
public String getIdentityInsertString()
Dialect
getIdentityInsertString
in class Dialect
public String getForUpdateString()
Dialect
getForUpdateString
in class Dialect
public boolean supportsUnique()
Dialect
supportsUnique
in class Dialect
public boolean supportsLimit()
Dialect
supportsLimit
in class Dialect
public String getLimitString(String sql, boolean hasOffset)
Dialect
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)
.
getLimitString
in class Dialect
sql
- The query to which to apply the limit.hasOffset
- Is the query requesting an offset?
public boolean bindLimitParametersInReverseOrder()
Dialect
bindLimitParametersInReverseOrder
in class Dialect
public boolean bindLimitParametersFirst()
Dialect
bindLimitParametersFirst
in class Dialect
public boolean supportsIfExistsAfterTableName()
supportsIfExistsAfterTableName
in class Dialect
public boolean supportsSequences()
Dialect
supportsSequences
in class Dialect
public boolean supportsPooledSequences()
Dialect
supportsPooledSequences
in class Dialect
Dialect.getCreateSequenceStrings(String, int, int)
,
Dialect.getCreateSequenceString(String, int, int)
public String getCreateSequenceString(String sequenceName)
Dialect
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)
.
getCreateSequenceString
in class Dialect
sequenceName
- The name of the sequence
public String getDropSequenceString(String sequenceName)
Dialect
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)
.
getDropSequenceString
in class Dialect
sequenceName
- The name of the sequence
public String getSelectSequenceNextValString(String sequenceName)
Dialect
Dialect.getSequenceNextValString(String)
in that this
should return an expression usable within another statement.
getSelectSequenceNextValString
in class Dialect
sequenceName
- the name of the sequence
public String getSequenceNextValString(String sequenceName)
Dialect
getSequenceNextValString
in class Dialect
sequenceName
- the name of the sequence
public String getQuerySequencesString()
Dialect
getQuerySequencesString
in class Dialect
SchemaUpdate
public ViolatedConstraintNameExtracter getViolatedConstraintNameExtracter()
getViolatedConstraintNameExtracter
in class Dialect
public boolean supportsTemporaryTables()
Dialect
supportsTemporaryTables
in class Dialect
public String getCreateTemporaryTableString()
Dialect
getCreateTemporaryTableString
in class Dialect
public Boolean performTemporaryTableDDLInIsolation()
Dialect
DatabaseMetaData.dataDefinitionCausesTransactionCommit()
method. However, that does not distinguish between temporary table
DDL and other forms of DDL; MySQL, for example, reports DDL causing a
transaction commit via its driver, even though that is not the case for
temporary table DDL.
Possible return values and their meanings:Boolean.TRUE
- Unequivocally, perform the temporary table DDL
in isolation.Boolean.FALSE
- Unequivocally, do not perform the
temporary table DDL in isolation.DatabaseMetaData.dataDefinitionCausesTransactionCommit()
performTemporaryTableDDLInIsolation
in class Dialect
public boolean dropTemporaryTableAfterUse()
Dialect
dropTemporaryTableAfterUse
in class Dialect
public boolean supportsCurrentTimestampSelection()
Dialect
supportsCurrentTimestampSelection
in class Dialect
public boolean isCurrentTimestampSelectStringCallable()
Dialect
Dialect.getCurrentTimestampSelectString()
be treated as callable. Typically this indicates that JDBC escape
syntax is being used...
isCurrentTimestampSelectStringCallable
in class Dialect
Dialect.getCurrentTimestampSelectString()
return
is callable; false otherwise.public String getCurrentTimestampSelectString()
Dialect
getCurrentTimestampSelectString
in class Dialect
public boolean supportsUnionAll()
Dialect
supportsUnionAll
in class Dialect
public boolean supportsLobValueChangePropogation()
Dialect
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()
.
supportsLobValueChangePropogation
in class Dialect
public boolean supportsTupleDistinctCounts()
Dialect
supportsTupleDistinctCounts
in class Dialect
public boolean doesReadCommittedCauseWritersToBlockReaders()
Dialect
doesReadCommittedCauseWritersToBlockReaders
in class Dialect
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