From a3a732b494d93445ae9c7f683b9e6b4960d38e42 Mon Sep 17 00:00:00 2001 From: Strong Liu Date: Mon, 1 Nov 2010 12:20:03 +0800 Subject: [PATCH] HHH-2655: make use of the ROW_NUMBER function --- .../dialect/SQLServer2008Dialect.java | 80 ++----------------- .../hibernate/dialect/SQLServerDialect.java | 80 ++++++++++++++++--- 2 files changed, 76 insertions(+), 84 deletions(-) diff --git a/hibernate-core/src/main/java/org/hibernate/dialect/SQLServer2008Dialect.java b/hibernate-core/src/main/java/org/hibernate/dialect/SQLServer2008Dialect.java index e1d8e505a2..fcf26c89fb 100644 --- a/hibernate-core/src/main/java/org/hibernate/dialect/SQLServer2008Dialect.java +++ b/hibernate-core/src/main/java/org/hibernate/dialect/SQLServer2008Dialect.java @@ -30,83 +30,17 @@ import org.hibernate.type.StandardBasicTypes; /** * A dialect for Microsoft SQL Server 2008 with JDBC Driver 3.0 and above - * + * * @author Gavin King */ public class SQLServer2008Dialect extends SQLServerDialect { public SQLServer2008Dialect() { - registerColumnType(Types.DATE, "date"); - registerColumnType(Types.TIME, "time"); - registerColumnType(Types.TIMESTAMP, "datetime2"); + registerColumnType( Types.DATE, "date" ); + registerColumnType( Types.TIME, "time" ); + registerColumnType( Types.TIMESTAMP, "datetime2" ); - registerFunction("current_timestamp", new NoArgSQLFunction("current_timestamp", StandardBasicTypes.TIMESTAMP, false)); - } - - /** - * Add a LIMIT clause to the given SQL SELECT (HHH-2655: ROW_NUMBER for Paging) - * - * The LIMIT SQL will look like: - * - * 
-	 * 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 
-	 * --ORDER BY __hibernate_row_nr__
-	 *
- * - * I don't think that the last order by clause is mandatory - * - * @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 super.getLimitString(querySqlString, offset, limit); - - StringBuilder sb = new StringBuilder(querySqlString.trim()); - - String querySqlLowered = querySqlString.trim().toLowerCase(); - int orderByIndex = querySqlLowered.toLowerCase().indexOf("order by"); - String orderby = orderByIndex > 0 ? querySqlString.substring(orderByIndex) : "ORDER BY CURRENT_TIMESTAMP"; - - // Delete the order by clause at the end of the query - if (orderByIndex > 0) sb.delete(orderByIndex, orderByIndex + orderby.length()); - - // Find the end of the select statement - int selectIndex = querySqlLowered.trim().startsWith("select distinct") ? 15 : 6; - - // Isert after the select statement the row_number() function: - sb.insert(selectIndex, " ROW_NUMBER() OVER (" + orderby + ") as __hibernate_row_nr__,"); - - // Wrap the query within a with statement: - sb.insert(0, "WITH query AS (").append(") SELECT * FROM query "); - sb.append("WHERE __hibernate_row_nr__ "); - - // The row_number() function is not zero based and so we must increment the offset and limit by one - if (offset > 0) sb.append("BETWEEN ").append(offset + 1).append(" AND ").append(limit + 1); - else sb.append(" <= ").append(limit); - - // As mentioned before I don't think that we really need this last order by clause - // sb.append(" ORDER BY __hibernate_row_nr__"); - return sb.toString(); - } - - @Override - public boolean supportsLimit() { - return true; - } - - @Override - public boolean supportsLimitOffset() { - return true; - } - - @Override - public boolean bindLimitParametersFirst() { - return false; + registerFunction( + "current_timestamp", new NoArgSQLFunction( "current_timestamp", StandardBasicTypes.TIMESTAMP, false ) + ); } } diff --git a/hibernate-core/src/main/java/org/hibernate/dialect/SQLServerDialect.java b/hibernate-core/src/main/java/org/hibernate/dialect/SQLServerDialect.java index f63292995b..b2fd2b384f 100644 --- a/hibernate-core/src/main/java/org/hibernate/dialect/SQLServerDialect.java +++ b/hibernate-core/src/main/java/org/hibernate/dialect/SQLServerDialect.java @@ -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; /** @@ -68,16 +68,68 @@ public class SQLServerDialect extends AbstractTransactSQLDialect { return selectIndex + ( selectDistinctIndex == selectIndex ? 15 : 6 ); } - public String getLimitString(String querySelect, int offset, int limit) { - if ( offset > 0 ) { - throw new UnsupportedOperationException( "query result offset is not supported" ); + /** + * Add a LIMIT clause to the given SQL SELECT (HHH-2655: ROW_NUMBER for Paging) + * + * The LIMIT SQL will look like: + * + * 
+	 * 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
+	 * --ORDER BY __hibernate_row_nr__
+	 *
+ * + * I don't think that the last order by clause is mandatory + * + * @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(); } - return new StringBuffer( querySelect.length() + 8 ) - .append( querySelect ) - .insert( getAfterSelectInsertPoint( querySelect ), " top " + limit ) - .toString(); + + StringBuilder sb = new StringBuilder( querySqlString.trim() ); + + String querySqlLowered = querySqlString.trim().toLowerCase(); + int orderByIndex = querySqlLowered.toLowerCase().indexOf( "order by" ); + String orderby = orderByIndex > 0 ? querySqlString.substring( orderByIndex ) : "ORDER BY CURRENT_TIMESTAMP"; + + // Delete the order by clause at the end of the query + if ( orderByIndex > 0 ) { + sb.delete( orderByIndex, orderByIndex + orderby.length() ); + } + + // Find the end of the select statement + int selectIndex = querySqlLowered.trim().startsWith( "select distinct" ) ? 15 : 6; + + // Isert after the select statement the row_number() function: + sb.insert( selectIndex, " ROW_NUMBER() OVER (" + orderby + ") as __hibernate_row_nr__," ); + + // Wrap the query within a with statement: + sb.insert( 0, "WITH query AS (" ).append( ") SELECT * FROM query " ); + sb.append( "WHERE __hibernate_row_nr__ " ); + + // The row_number() function is not zero based and so we must increment the offset and limit by one + if ( offset > 0 ) { + sb.append( "BETWEEN " ).append( offset + 1 ).append( " AND " ).append( limit + 1 ); + } + else { + sb.append( " <= " ).append( limit ); + } + + // As mentioned before I don't think that we really need this last order by clause + // sb.append(" ORDER BY __hibernate_row_nr__"); + return sb.toString(); } + /** * Use insert table(...) values(...) select SCOPE_IDENTITY() */ @@ -94,6 +146,11 @@ public class SQLServerDialect extends AbstractTransactSQLDialect { } public boolean supportsLimitOffset() { + return true; + } + + @Override + public boolean bindLimitParametersFirst() { return false; } @@ -111,9 +168,9 @@ 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 ) { @@ -126,6 +183,7 @@ 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"; }