From d409bb80b1f8d0738c47086eb72d8f1dbedc6aae Mon Sep 17 00:00:00 2001
From: Marcel Loose <loose@astron.nl>
Date: Mon, 22 Dec 2003 11:03:47 +0000
Subject: [PATCH] %[ER: 65]% Added SQL-like operator like BETWEEN, IN, and
LIKE. Fixed couple of bugs.
---
.../PL/include/PL/Query/BinaryExprNode.h | 4 +-
.../PL/include/PL/Query/ConstExprNode.h | 3 +-
LCS/databases/PL/include/PL/Query/Expr.h | 28 +++++++-
LCS/databases/PL/include/PL/Query/ExprNode.h | 4 +-
.../PL/include/PL/Query/SQLExprNode.h | 19 +++++-
.../PL/include/PL/Query/UnaryExprNode.h | 3 +
LCS/databases/PL/src/Query/BinaryExprNode.cc | 8 ++-
LCS/databases/PL/src/Query/BinaryExprNode.h | 4 +-
LCS/databases/PL/src/Query/ConstExprNode.h | 3 +-
LCS/databases/PL/src/Query/Expr.cc | 47 ++++++++++++-
LCS/databases/PL/src/Query/Expr.h | 28 +++++++-
LCS/databases/PL/src/Query/ExprNode.h | 4 +-
LCS/databases/PL/src/Query/SQLExprNode.cc | 66 +++++++++++++------
LCS/databases/PL/src/Query/SQLExprNode.h | 19 +++++-
LCS/databases/PL/src/Query/UnaryExprNode.cc | 2 +-
LCS/databases/PL/src/Query/UnaryExprNode.h | 3 +
16 files changed, 199 insertions(+), 46 deletions(-)
diff --git a/LCS/databases/PL/include/PL/Query/BinaryExprNode.h b/LCS/databases/PL/include/PL/Query/BinaryExprNode.h
index 95cb3a9d293..45bed3f5bb9 100644
--- a/LCS/databases/PL/include/PL/Query/BinaryExprNode.h
+++ b/LCS/databases/PL/include/PL/Query/BinaryExprNode.h
@@ -56,8 +56,8 @@ namespace LOFAR
private:
- // @name The operator
- const std::string itsOperand;
+ // @name The operation
+ const std::string itsOperation;
// @name The operands
//@{
diff --git a/LCS/databases/PL/include/PL/Query/ConstExprNode.h b/LCS/databases/PL/include/PL/Query/ConstExprNode.h
index 1f91da3589d..4acf1780592 100644
--- a/LCS/databases/PL/include/PL/Query/ConstExprNode.h
+++ b/LCS/databases/PL/include/PL/Query/ConstExprNode.h
@@ -39,8 +39,9 @@ namespace LOFAR
{
//# Forward Declarations
- // @defgroup ConstExprNode
+ // @defgroup ConstExprNode Constant Expression Nodes
// @ingroup ExprNode
+ //
// These classes represent constant expression nodes. A constant
// expression is an expression that can be evaluated compile-time and
// has a primitive type like int, double or string.
diff --git a/LCS/databases/PL/include/PL/Query/Expr.h b/LCS/databases/PL/include/PL/Query/Expr.h
index 6a0ee817e0e..f8934b5a2af 100644
--- a/LCS/databases/PL/include/PL/Query/Expr.h
+++ b/LCS/databases/PL/include/PL/Query/Expr.h
@@ -37,12 +37,12 @@ namespace LOFAR
{
namespace PL
{
+ template<typename T> class Collection;
+
namespace Query
{
- //# Forward Declarations
-
- // An Expr represents the WHERE clause of a query.
+ // This class represents the WHERE clause of a query.
class Expr
{
public:
@@ -53,6 +53,7 @@ namespace LOFAR
Expr(int value);
Expr(double value);
Expr(const std::string& value);
+ Expr(const char* const value);
//@}
// Construct an Expr from an ExprNode pointer.
@@ -67,6 +68,27 @@ namespace LOFAR
Expr operator! () const;
//@}
+ //@{
+ // The BETWEEN operator is used to test if a value is within an
+ // interval.
+ Expr between(const Expr& lhs, const Expr& rhs) const;
+ Expr notBetween(const Expr& lhs, const Expr& rhs) const;
+ //@}
+
+ //@{
+ // The IN operator is used to test if an expression is contained in a
+ // set of expressions.
+ Expr in (const Collection<Expr>& set) const;
+ Expr notIn(const Collection<Expr>& set) const;
+ //@}
+
+ //@{
+ // The LIKE operator is used to test if a value has a match with a
+ // pattern expression.
+ Expr like(const Expr& exp) const;
+ Expr notLike(const Expr& exp) const;
+ //@}
+
private:
// @name Arithmetic operators
diff --git a/LCS/databases/PL/include/PL/Query/ExprNode.h b/LCS/databases/PL/include/PL/Query/ExprNode.h
index 5c4b9cd3b55..20910394667 100644
--- a/LCS/databases/PL/include/PL/Query/ExprNode.h
+++ b/LCS/databases/PL/include/PL/Query/ExprNode.h
@@ -39,8 +39,8 @@ namespace LOFAR
//# Forward Declarations
class Expr;
- // @defgroup ExprNode
-
+ // @defgroup ExprNode Expression Nodes
+ //
// ExprNode is an abstract base class that represents the node of an
// expression query. We will need to derive specific expression node
// classes (e.g. ExprNodeBinary) from it.
diff --git a/LCS/databases/PL/include/PL/Query/SQLExprNode.h b/LCS/databases/PL/include/PL/Query/SQLExprNode.h
index 68aa76ce2ce..b8a08cb99ac 100644
--- a/LCS/databases/PL/include/PL/Query/SQLExprNode.h
+++ b/LCS/databases/PL/include/PL/Query/SQLExprNode.h
@@ -83,6 +83,8 @@ namespace LOFAR
// expression that takes one operator (IN or NOT IN) and two
// operands. It is used to check whether the first operand is present in
// the second operand.
+ // \note When \c rhs contains no elements only the \c lhs will be
+ // returned when you invoke print() on InExprNode.
class InExprNode : public ExprNode
{
public:
@@ -116,7 +118,22 @@ namespace LOFAR
// The user-supplied pattern can contain the wildcards "*" and "?",
// where "*" means any number of characters, and "?" means exactly one
// character. These wildcards will be translated to their
- // SQL-equivalents "%" and "_" respectively.
+ // SQL-equivalents "%" and "_" respectively.
+ //
+ // We will use the backslash character (\) as escape character in the
+ // LIKE clause. As the backslash character needs to be escaped itself,
+ // we always have to provide two backslash characters as the escape
+ // token.
+ //
+ // Hence we get the following substitution scheme:
+ // \verbatim
+ // '*' --> '%'
+ // '?' --> '_'
+ // '\*' --> '*'
+ // '\?' --> '?'
+ // '_' --> '\\_'
+ // '%' --> '\\%'
+ // \endverbatim
class LikeExprNode : public ExprNode
{
public:
diff --git a/LCS/databases/PL/include/PL/Query/UnaryExprNode.h b/LCS/databases/PL/include/PL/Query/UnaryExprNode.h
index 4e91e6ea8c7..552eeccbbe2 100644
--- a/LCS/databases/PL/include/PL/Query/UnaryExprNode.h
+++ b/LCS/databases/PL/include/PL/Query/UnaryExprNode.h
@@ -48,6 +48,9 @@ namespace LOFAR
UnaryExprNode(const std::string& oper,
const Expr& value);
+// UnaryExprNode(const std::string& oper,
+// const ExprNodeSet& set);
+
virtual ~UnaryExprNode();
virtual void print(std::ostream& os);
diff --git a/LCS/databases/PL/src/Query/BinaryExprNode.cc b/LCS/databases/PL/src/Query/BinaryExprNode.cc
index 68ab4093fa7..3937d261280 100644
--- a/LCS/databases/PL/src/Query/BinaryExprNode.cc
+++ b/LCS/databases/PL/src/Query/BinaryExprNode.cc
@@ -32,16 +32,18 @@ namespace LOFAR
BinaryExprNode::BinaryExprNode(const std::string& oper,
const Expr& lhs, const Expr& rhs) :
- itsOperand(oper),
+ itsOperation(oper),
itsLeft(lhs), itsRight(rhs)
{
}
- BinaryExprNode::~BinaryExprNode() {}
+ BinaryExprNode::~BinaryExprNode()
+ {
+ }
void BinaryExprNode::print(std::ostream& os)
{
- os << "(" << itsLeft << itsOperand << itsRight << ")";
+ os << "(" << itsLeft << itsOperation << itsRight << ")";
}
} // namespace Query
diff --git a/LCS/databases/PL/src/Query/BinaryExprNode.h b/LCS/databases/PL/src/Query/BinaryExprNode.h
index 95cb3a9d293..45bed3f5bb9 100644
--- a/LCS/databases/PL/src/Query/BinaryExprNode.h
+++ b/LCS/databases/PL/src/Query/BinaryExprNode.h
@@ -56,8 +56,8 @@ namespace LOFAR
private:
- // @name The operator
- const std::string itsOperand;
+ // @name The operation
+ const std::string itsOperation;
// @name The operands
//@{
diff --git a/LCS/databases/PL/src/Query/ConstExprNode.h b/LCS/databases/PL/src/Query/ConstExprNode.h
index 1f91da3589d..4acf1780592 100644
--- a/LCS/databases/PL/src/Query/ConstExprNode.h
+++ b/LCS/databases/PL/src/Query/ConstExprNode.h
@@ -39,8 +39,9 @@ namespace LOFAR
{
//# Forward Declarations
- // @defgroup ConstExprNode
+ // @defgroup ConstExprNode Constant Expression Nodes
// @ingroup ExprNode
+ //
// These classes represent constant expression nodes. A constant
// expression is an expression that can be evaluated compile-time and
// has a primitive type like int, double or string.
diff --git a/LCS/databases/PL/src/Query/Expr.cc b/LCS/databases/PL/src/Query/Expr.cc
index 680b55aac13..300e04797f3 100644
--- a/LCS/databases/PL/src/Query/Expr.cc
+++ b/LCS/databases/PL/src/Query/Expr.cc
@@ -24,6 +24,7 @@
#include <PL/Query/ConstExprNode.h>
#include <PL/Query/UnaryExprNode.h>
#include <PL/Query/BinaryExprNode.h>
+#include <PL/Query/SQLExprNode.h>
#include <iostream>
using std::ostream;
@@ -56,6 +57,11 @@ namespace LOFAR
itsNode(new StringExprNode(value))
{
}
+
+ Expr::Expr(const char* const value) :
+ itsNode(new StringExprNode(value))
+ {
+ }
Expr::Expr(ExprNode* const node) :
itsNode(node)
@@ -79,7 +85,7 @@ namespace LOFAR
Expr Expr::operator! () const
{
- return new UnaryExprNode("NOT", *this);
+ return new UnaryExprNode("NOT ", *this);
}
@@ -149,12 +155,47 @@ namespace LOFAR
Expr operator&& (const Expr& lhs, const Expr& rhs)
{
- return new BinaryExprNode("AND", lhs, rhs);
+ return new BinaryExprNode(" AND ", lhs, rhs);
}
Expr operator|| (const Expr& lhs, const Expr& rhs)
{
- return new BinaryExprNode("OR", lhs, rhs);
+ return new BinaryExprNode(" OR ", lhs, rhs);
+ }
+
+
+ ///////////////////////////////////////////////////////////////////
+ // SQL-like operators //
+ ///////////////////////////////////////////////////////////////////
+
+ Expr Expr::between (const Expr& lhs, const Expr& rhs) const
+ {
+ return new BetweenExprNode(" BETWEEN ", *this, lhs, rhs);
+ }
+
+ Expr Expr::notBetween (const Expr& lhs, const Expr& rhs) const
+ {
+ return new BetweenExprNode(" NOT BETWEEN ", *this, lhs, rhs);
+ }
+
+ Expr Expr::in (const Collection<Expr>& set) const
+ {
+ return new InExprNode(" IN ", *this, set);
+ }
+
+ Expr Expr::notIn (const Collection<Expr>& set) const
+ {
+ return new InExprNode(" NOT IN ", *this, set);
+ }
+
+ Expr Expr::like (const Expr& exp) const
+ {
+ return new LikeExprNode(" LIKE ", *this, exp);
+ }
+
+ Expr Expr::notLike (const Expr& exp) const
+ {
+ return new LikeExprNode(" NOT LIKE ", *this, exp);
}
diff --git a/LCS/databases/PL/src/Query/Expr.h b/LCS/databases/PL/src/Query/Expr.h
index 6a0ee817e0e..f8934b5a2af 100644
--- a/LCS/databases/PL/src/Query/Expr.h
+++ b/LCS/databases/PL/src/Query/Expr.h
@@ -37,12 +37,12 @@ namespace LOFAR
{
namespace PL
{
+ template<typename T> class Collection;
+
namespace Query
{
- //# Forward Declarations
-
- // An Expr represents the WHERE clause of a query.
+ // This class represents the WHERE clause of a query.
class Expr
{
public:
@@ -53,6 +53,7 @@ namespace LOFAR
Expr(int value);
Expr(double value);
Expr(const std::string& value);
+ Expr(const char* const value);
//@}
// Construct an Expr from an ExprNode pointer.
@@ -67,6 +68,27 @@ namespace LOFAR
Expr operator! () const;
//@}
+ //@{
+ // The BETWEEN operator is used to test if a value is within an
+ // interval.
+ Expr between(const Expr& lhs, const Expr& rhs) const;
+ Expr notBetween(const Expr& lhs, const Expr& rhs) const;
+ //@}
+
+ //@{
+ // The IN operator is used to test if an expression is contained in a
+ // set of expressions.
+ Expr in (const Collection<Expr>& set) const;
+ Expr notIn(const Collection<Expr>& set) const;
+ //@}
+
+ //@{
+ // The LIKE operator is used to test if a value has a match with a
+ // pattern expression.
+ Expr like(const Expr& exp) const;
+ Expr notLike(const Expr& exp) const;
+ //@}
+
private:
// @name Arithmetic operators
diff --git a/LCS/databases/PL/src/Query/ExprNode.h b/LCS/databases/PL/src/Query/ExprNode.h
index 5c4b9cd3b55..20910394667 100644
--- a/LCS/databases/PL/src/Query/ExprNode.h
+++ b/LCS/databases/PL/src/Query/ExprNode.h
@@ -39,8 +39,8 @@ namespace LOFAR
//# Forward Declarations
class Expr;
- // @defgroup ExprNode
-
+ // @defgroup ExprNode Expression Nodes
+ //
// ExprNode is an abstract base class that represents the node of an
// expression query. We will need to derive specific expression node
// classes (e.g. ExprNodeBinary) from it.
diff --git a/LCS/databases/PL/src/Query/SQLExprNode.cc b/LCS/databases/PL/src/Query/SQLExprNode.cc
index 6a19816a5fb..2a7d30f815c 100644
--- a/LCS/databases/PL/src/Query/SQLExprNode.cc
+++ b/LCS/databases/PL/src/Query/SQLExprNode.cc
@@ -67,18 +67,18 @@ namespace LOFAR
void InExprNode::print(std::ostream& os)
{
- ostringstream oss;
- Collection<Expr>::const_iterator it;
- for (it = itsRight.begin(); it != itsRight.end(); ++it) {
- oss << *it << ",";
- }
- // Convert oss to a string; strip last comma if there is one
- string s(oss.str());
- string::size_type idx;
- if ((idx = s.rfind(",")) != string::npos) {
- s.erase(idx);
+ os << "(" << itsLeft;
+ if (!itsRight.empty()) {
+ ostringstream oss;
+ Collection<Expr>::const_iterator it;
+ for (it = itsRight.begin(); it != itsRight.end(); ++it) {
+ oss << *it << ",";
+ }
+ string s(oss.str()); // convert oss to a string
+ s.erase(s.size()-1); // strip trailing comma
+ os << itsOperation << "(" << s << ")";
}
- os << "(" << itsLeft << itsOperation << "(" << s << "))";
+ os << ")";
}
@@ -95,18 +95,42 @@ namespace LOFAR
void LikeExprNode::print(std::ostream& os)
{
- // Scan the pattern expression for occurrences of "*" and "?".
- // We have to check whether these characters are escaped!
- std::string s;
- bool isEscaped = false;
-// for(string::size_type idx = 0; idx < itsRight.size(); ++idx) {
-// isEscaped = (itsRight[idx] == '\\');
-// if (isEscaped) {
-
-// }
-// }
+ ostringstream oss;
+ oss << itsRight;
+ string rhs(oss.str());
+ string pattern;
+
+ // Scan the pattern expression in itsRight for occurrences of wildcard
+ // characters and make the proper substitutions.
+ for(string::const_iterator it = rhs.begin(); it != rhs.end(); ++it) {
+ switch (*it) {
+ case '*':
+ pattern += "%";
+ break;
+ case '?':
+ pattern += "_";
+ break;
+ case '%':
+ pattern += "\\\\%";
+ break;
+ case '_':
+ pattern += "\\\\_";
+ break;
+ case '\\':
+ if (++it != rhs.end())
+ if (*it == '\\') pattern += "\\\\\\\\";
+ else pattern += *it;
+ break;
+ default:
+ pattern += *it;
+ break;
+ }
+ }
+
+ os << "(" << itsLeft << itsOperation << pattern << " ESCAPE '\\\\')";
}
+
} // namespace Query
} // namespace PL
diff --git a/LCS/databases/PL/src/Query/SQLExprNode.h b/LCS/databases/PL/src/Query/SQLExprNode.h
index 68aa76ce2ce..b8a08cb99ac 100644
--- a/LCS/databases/PL/src/Query/SQLExprNode.h
+++ b/LCS/databases/PL/src/Query/SQLExprNode.h
@@ -83,6 +83,8 @@ namespace LOFAR
// expression that takes one operator (IN or NOT IN) and two
// operands. It is used to check whether the first operand is present in
// the second operand.
+ // \note When \c rhs contains no elements only the \c lhs will be
+ // returned when you invoke print() on InExprNode.
class InExprNode : public ExprNode
{
public:
@@ -116,7 +118,22 @@ namespace LOFAR
// The user-supplied pattern can contain the wildcards "*" and "?",
// where "*" means any number of characters, and "?" means exactly one
// character. These wildcards will be translated to their
- // SQL-equivalents "%" and "_" respectively.
+ // SQL-equivalents "%" and "_" respectively.
+ //
+ // We will use the backslash character (\) as escape character in the
+ // LIKE clause. As the backslash character needs to be escaped itself,
+ // we always have to provide two backslash characters as the escape
+ // token.
+ //
+ // Hence we get the following substitution scheme:
+ // \verbatim
+ // '*' --> '%'
+ // '?' --> '_'
+ // '\*' --> '*'
+ // '\?' --> '?'
+ // '_' --> '\\_'
+ // '%' --> '\\%'
+ // \endverbatim
class LikeExprNode : public ExprNode
{
public:
diff --git a/LCS/databases/PL/src/Query/UnaryExprNode.cc b/LCS/databases/PL/src/Query/UnaryExprNode.cc
index 343f8cdee74..d68350e9f92 100644
--- a/LCS/databases/PL/src/Query/UnaryExprNode.cc
+++ b/LCS/databases/PL/src/Query/UnaryExprNode.cc
@@ -42,7 +42,7 @@ namespace LOFAR
void UnaryExprNode::print(std::ostream& os)
{
- os << itsOperation << "(" << itsOperand << ")";
+ os << "(" << itsOperation << itsOperand << ")";
}
} // namespace Query
diff --git a/LCS/databases/PL/src/Query/UnaryExprNode.h b/LCS/databases/PL/src/Query/UnaryExprNode.h
index 4e91e6ea8c7..552eeccbbe2 100644
--- a/LCS/databases/PL/src/Query/UnaryExprNode.h
+++ b/LCS/databases/PL/src/Query/UnaryExprNode.h
@@ -48,6 +48,9 @@ namespace LOFAR
UnaryExprNode(const std::string& oper,
const Expr& value);
+// UnaryExprNode(const std::string& oper,
+// const ExprNodeSet& set);
+
virtual ~UnaryExprNode();
virtual void print(std::ostream& os);
--
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