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SQLServerDialect fallback to the pre HHH-2655 one

This commit is contained in:
Yoryos Valotasios 2010-11-10 22:03:47 +02:00
parent 6e565102b5
commit 2ec009440e
1 changed files with 13 additions and 111 deletions
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124
hibernate-core/src/main/java/org/hibernate/dialect/SQLServerDialect.java
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@ -26,9 +26,9 @@ package org.hibernate.dialect;
import java.sql.Types;
import org.hibernate.LockMode;
import org.hibernate.dialect.function.AnsiTrimEmulationFunction;
import org.hibernate.dialect.function.SQLFunctionTemplate;
import org.hibernate.dialect.function.StandardSQLFunction;
import org.hibernate.dialect.function.AnsiTrimEmulationFunction;
import org.hibernate.type.StandardBasicTypes;
/**
@ -37,11 +37,7 @@ import org.hibernate.type.StandardBasicTypes;
* @author Gavin King
*/
public class SQLServerDialect extends AbstractTransactSQLDialect {
private static final String SELECT = "select";
private static final String FROM = "from";
private static final String DISTINCT = "distinct";
public SQLServerDialect() {
registerColumnType( Types.VARBINARY, "image" );
registerColumnType( Types.VARBINARY, 8000, "varbinary($l)" );
@ -72,103 +68,14 @@ public class SQLServerDialect extends AbstractTransactSQLDialect {
return selectIndex + ( selectDistinctIndex == selectIndex ? 15 : 6 );
}
/**
* Add a LIMIT clause to the given SQL SELECT (HHH-2655: ROW_NUMBER for Paging)
*
* The LIMIT SQL will look like:
*
* <pre>
* WITH query AS (SELECT ROW_NUMBER() OVER (ORDER BY orderby) as __hibernate_row_nr__, original_query_without_orderby)
* SELECT * FROM query WHERE __hibernate_row_nr__ BEETWIN offset AND offset + last
* </pre>
*
*
* @param querySqlString The SQL statement to base the limit query off of.
* @param offset Offset of the first row to be returned by the query (zero-based)
* @param limit Maximum number of rows to be returned by the query
*
* @return A new SQL statement with the LIMIT clause applied.
*/
@Override
public String getLimitString(String querySqlString, int offset, int limit) {
if ( offset == 0 ) {
return new StringBuffer( querySqlString.length() + 8 ).append( querySqlString )
.insert( getAfterSelectInsertPoint( querySqlString ), " top " + limit )
.toString();
public String getLimitString(String querySelect, int offset, int limit) {
if ( offset > 0 ) {
throw new UnsupportedOperationException( "query result offset is not supported" );
}
StringBuilder sb = new StringBuilder( querySqlString.trim().toLowerCase() );
int orderByIndex = sb.indexOf( "order by" );
CharSequence orderby = orderByIndex > 0 ? sb.subSequence( orderByIndex, sb.length() ) : "ORDER BY CURRENT_TIMESTAMP";
// Delete the order by clause at the end of the query
if ( orderByIndex > 0 ) {
sb.delete( orderByIndex, orderByIndex + orderby.length() );
}
// HHH-5715 bug fix
replaceDistinctWithGroupBy( sb );
insertRowNumberFunction( sb, orderby );
//Wrap the query within a with statement:
sb.insert( 0, "WITH query AS (").append(") SELECT * FROM query " );
sb.append( "WHERE __hibernate_row_nr__ BETWEEN " ).append(offset + 1).append( " AND " ).append( limit );
return sb.toString();
}
/**
* Utility method that checks if the given sql query is a select distinct one and if so replaces the distinct
* select with an equivelant simple select with a group by clause. See {@link SQLServerDialectTestCase#testReplaceDistinctWithGroupBy()}
*
* @param an sql query
*/
protected static void replaceDistinctWithGroupBy(StringBuilder sql) {
int distinctIndex = sql.indexOf( DISTINCT );
if (distinctIndex > 0) {
sql.delete(distinctIndex, distinctIndex + DISTINCT.length() + 1);
sql.append(" group by").append(getSelectFieldsWithoutAliases(sql));
}
}
/**
* This utility method searches the given sql query for the fields of the select statement and
* returns them without the aliases. See {@link SQLServerDialectTestCase#testGetSelectFieldsWithoutAliases()}
*
* @param an sql query
* @return the fields of the select statement without their alias
*/
protected static CharSequence getSelectFieldsWithoutAliases(StringBuilder sql) {
String select = sql.substring( sql.indexOf(SELECT) + SELECT.length(), sql.indexOf(FROM));
// Strip the as clauses
return stripAliases( select );
}
/**
* Utility method that strips the aliases. See {@link SQLServerDialectTestCase#testStripAliases()}
*
* @param a string to replace the as statements
* @return a string without the as statements
*/
protected static String stripAliases(String str) {
return str.replaceAll( "\\sas[^,]+(,?)", "$1" );
}
/**
* Right after the select statement of a given query we must place the row_number function
*
* @param sql the initial sql query without the order by clause
* @param orderby the order by clause of the query
*/
protected static void insertRowNumberFunction(StringBuilder sql, CharSequence orderby) {
// Find the end of the select statement
int selectEndIndex = sql.indexOf( SELECT ) + SELECT.length();
// Isert after the select statement the row_number() function:
sql.insert( selectEndIndex, " ROW_NUMBER() OVER (" + orderby + ") as __hibernate_row_nr__," );
return new StringBuffer( querySelect.length() + 8 )
.append( querySelect )
.insert( getAfterSelectInsertPoint( querySelect ), " top " + limit )
.toString();
}
/**
@ -187,11 +94,6 @@ public class SQLServerDialect extends AbstractTransactSQLDialect {
}
public boolean supportsLimitOffset() {
return true;
}
@Override
public boolean bindLimitParametersFirst() {
return false;
}
@ -209,9 +111,9 @@ public class SQLServerDialect extends AbstractTransactSQLDialect {
public String appendLockHint(LockMode mode, String tableName) {
if ( ( mode == LockMode.UPGRADE ) ||
( mode == LockMode.UPGRADE_NOWAIT ) ||
( mode == LockMode.PESSIMISTIC_WRITE ) ||
( mode == LockMode.WRITE ) ) {
( mode == LockMode.UPGRADE_NOWAIT ) ||
( mode == LockMode.PESSIMISTIC_WRITE ) ||
( mode == LockMode.WRITE ) ) {
return tableName + " with (updlock, rowlock)";
}
else if ( mode == LockMode.PESSIMISTIC_READ ) {
@ -224,7 +126,6 @@ public class SQLServerDialect extends AbstractTransactSQLDialect {
// The current_timestamp is more accurate, but only known to be supported
// in SQL Server 7.0 and later (i.e., Sybase not known to support it at all)
public String getCurrentTimestampSelectString() {
return "select current_timestamp";
}
@ -260,3 +161,4 @@ public class SQLServerDialect extends AbstractTransactSQLDialect {
}
}