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Determine ansinull setting for Sybase ASE and implement proper comparison handling when it is off

This commit is contained in:
Christian Beikov 2021-09-02 13:07:40 +02:00
parent c71171a762
commit 9e4e9ce0d5
7 changed files with 135 additions and 24 deletions
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4
hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java
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@ -3103,6 +3103,10 @@ public abstract class Dialect implements ConversionContext {
return true;
}
public boolean isAnsiNullOn() {
return true;
}
/**
* Renders an ordering fragment
*

2
hibernate-core/src/main/java/org/hibernate/dialect/Sybase11Dialect.java
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@ -16,6 +16,6 @@ package org.hibernate.dialect;
@Deprecated
public class Sybase11Dialect extends SybaseASEDialect {
public Sybase11Dialect() {
super( 1100, false );
super( 1100, false, false );
}
}

2
hibernate-core/src/main/java/org/hibernate/dialect/SybaseASE157Dialect.java
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@ -17,7 +17,7 @@ package org.hibernate.dialect;
public class SybaseASE157Dialect extends SybaseASEDialect {
public SybaseASE157Dialect() {
super( 1570, false );
super( 1570, false, false );
}
}

2
hibernate-core/src/main/java/org/hibernate/dialect/SybaseASE15Dialect.java
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@ -17,7 +17,7 @@ package org.hibernate.dialect;
public class SybaseASE15Dialect extends SybaseASEDialect {
public SybaseASE15Dialect() {
super( 1500, false );
super( 1500, false, false );
}
}

35
hibernate-core/src/main/java/org/hibernate/dialect/SybaseASEDialect.java
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@ -6,6 +6,9 @@
*/
package org.hibernate.dialect;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import java.util.Map;
@ -48,21 +51,23 @@ import static org.hibernate.exception.spi.TemplatedViolatedConstraintNameExtract
public class SybaseASEDialect extends SybaseDialect {
private final SizeStrategy sizeStrategy;
private final boolean ansiNull;
public SybaseASEDialect() {
this( 1100, false );
this( 1100, false, false );
}
public SybaseASEDialect(DialectResolutionInfo info) {
this(
info.getDatabaseMajorVersion() * 100 + info.getDatabaseMinorVersion() * 10,
info.getDriverName() != null && info.getDriverName().contains( "jTDS" )
info.getDriverName() != null && info.getDriverName().contains( "jTDS" ),
isAnsiNull( info.unwrap( DatabaseMetaData.class ) )
);
}
public SybaseASEDialect(int version, boolean jtdsDriver) {
public SybaseASEDialect(int version, boolean jtdsDriver, boolean ansiNull) {
super( version, jtdsDriver );
this.ansiNull = ansiNull;
//On Sybase ASE, the 'bit' type cannot be null,
//and cannot have indexes (while we don't use
//tinyint to store signed bytes, we can use it
@ -121,6 +126,28 @@ public class SybaseASEDialect extends SybaseDialect {
};
}
private static boolean isAnsiNull(DatabaseMetaData databaseMetaData) {
if ( databaseMetaData != null ) {
try (java.sql.Statement s = databaseMetaData.getConnection().createStatement() ) {
final ResultSet rs = s.executeQuery( "SELECT @@options" );
if ( rs.next() ) {
final byte[] optionBytes = rs.getBytes( 1 );
// By trial and error, enabling and disabling ansinull revealed that this bit is the indicator
return ( optionBytes[4] & 2 ) == 2;
}
}
catch (SQLException ex) {
// Ignore
}
}
return false;
}
@Override
public boolean isAnsiNullOn() {
return ansiNull;
}
@Override
public int getDoublePrecision() {
return 48;

80
hibernate-core/src/main/java/org/hibernate/dialect/SybaseASESqlAstTranslator.java
View File

@ -19,7 +19,9 @@ import org.hibernate.sql.ast.tree.Statement;
import org.hibernate.sql.ast.tree.cte.CteStatement;
import org.hibernate.sql.ast.tree.expression.ColumnReference;
import org.hibernate.sql.ast.tree.expression.Expression;
import org.hibernate.sql.ast.tree.expression.JdbcParameter;
import org.hibernate.sql.ast.tree.expression.Literal;
import org.hibernate.sql.ast.tree.expression.NullnessLiteral;
import org.hibernate.sql.ast.tree.expression.SqlTuple;
import org.hibernate.sql.ast.tree.expression.Summarization;
import org.hibernate.sql.ast.tree.from.TableGroup;
@ -152,24 +154,68 @@ public class SybaseASESqlAstTranslator<T extends JdbcOperation> extends Abstract
@Override
protected void renderComparison(Expression lhs, ComparisonOperator operator, Expression rhs) {
// I think intersect is only supported in 16.0 SP3
// renderComparisonEmulateIntersect( lhs, operator, rhs );
lhs.accept( this );
appendSql( " " );
// This relies on the fact that Sybase usually is configured with ANSINULLS OFF
switch ( operator ) {
case DISTINCT_FROM:
appendSql( "<>" );
break;
case NOT_DISTINCT_FROM:
appendSql( '=' );
break;
default:
appendSql( operator.sqlText() );
break;
if ( getDialect().isAnsiNullOn() ) {
if ( getDialect().getVersion() >= 1630 ) {
renderComparisonEmulateIntersect( lhs, operator, rhs );
}
else {
renderComparisonEmulateCase( lhs, operator, rhs );
}
}
else {
// The ansinull setting only matters if using a parameter or literal and the eq operator according to the docs
// http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.infocenter.dc32300.1570/html/sqlug/sqlug89.htm
boolean rhsNotNullPredicate =
lhs instanceof NullnessLiteral
|| lhs instanceof Literal
|| lhs instanceof JdbcParameter;
boolean lhsNotNullPredicate =
rhs instanceof NullnessLiteral
|| rhs instanceof Literal
|| rhs instanceof JdbcParameter;
if ( rhsNotNullPredicate || lhsNotNullPredicate ) {
lhs.accept( this );
appendSql( " " );
switch ( operator ) {
case DISTINCT_FROM:
appendSql( "<>" );
break;
case NOT_DISTINCT_FROM:
appendSql( '=' );
break;
case LESS_THAN:
case GREATER_THAN:
case LESS_THAN_OR_EQUAL:
case GREATER_THAN_OR_EQUAL:
// These operators are not affected by ansinull=off
lhsNotNullPredicate = false;
rhsNotNullPredicate = false;
default:
appendSql( operator.sqlText() );
break;
}
appendSql( " " );
rhs.accept( this );
if ( lhsNotNullPredicate ) {
appendSql( " and " );
lhs.accept( this );
appendSql( " is not null" );
}
if ( rhsNotNullPredicate ) {
appendSql( " and " );
rhs.accept( this );
appendSql( " is not null" );
}
}
else {
if ( getDialect().getVersion() >= 1630 ) {
renderComparisonEmulateIntersect( lhs, operator, rhs );
}
else {
renderComparisonEmulateCase( lhs, operator, rhs );
}
}
}
appendSql( " " );
rhs.accept( this );
}
@Override

34
hibernate-core/src/main/java/org/hibernate/sql/ast/spi/AbstractSqlAstTranslator.java
View File

@ -1994,6 +1994,40 @@ public abstract class AbstractSqlAstTranslator<T extends JdbcOperation> implemen
}
}
protected void renderComparisonEmulateCase(Expression lhs, ComparisonOperator operator, Expression rhs) {
switch ( operator ) {
case DISTINCT_FROM:
appendSql( "case when " );
lhs.accept( this );
appendSql( " = " );
rhs.accept( this );
appendSql( " or " );
lhs.accept( this );
appendSql( " is null and " );
rhs.accept( this );
appendSql( " is null then 0 else 1 end = 1" );
break;
case NOT_DISTINCT_FROM:
appendSql( "case when " );
lhs.accept( this );
appendSql( " = " );
rhs.accept( this );
appendSql( " or " );
lhs.accept( this );
appendSql( " is null and " );
rhs.accept( this );
appendSql( " is null then 0 else 1 end = 0" );
break;
default:
lhs.accept( this );
appendSql( ' ' );
appendSql( operator.sqlText() );
appendSql( ' ' );
rhs.accept( this );
break;
}
}
protected void renderComparisonEmulateIntersect(Expression lhs, ComparisonOperator operator, Expression rhs) {
switch ( operator ) {
case DISTINCT_FROM: