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nathanlws/Paramer.java

Last active August 29, 2015 13:57
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SQL Parser Paramer
Raw
notes.md

Example output:

$ java -cp target/classes/ com.foundationdb.sql.ParamerDemo "SELECT * FROM USERS WHERE NAME ='BOB' AND ID=123 AND STATUS=TRUE"
 pre: SELECT * FROM USERS WHERE NAME ='BOB' AND ID=123 AND STATUS=TRUE
post: SELECT * FROM users WHERE ((name = $1) AND (id = $2)) AND (status = $3)
  $1 => BOB (String)
  $2 => 123 (Integer)
  $3 => true (Boolean)

Extensions:

  • Avoiding transformation of clauses outside of the WHERE (e.g. SELECT a = 'YES' ...)
  • Detecting equivalent values (e.g. WHERE a = 5 AND b = 5)
  • Parameterizing more node types (e.g. BetweenOperatorNode)
Raw
Paramer.java
import com.foundationdb.sql.parser.BinaryRelationalOperatorNode;
import com.foundationdb.sql.parser.ConstantNode;
import com.foundationdb.sql.parser.NodeTypes;
import com.foundationdb.sql.parser.ParameterNode;
import com.foundationdb.sql.parser.Visitable;
import com.foundationdb.sql.parser.Visitor;
import java.util.LinkedHashMap;
import java.util.Map;
public class Paramer implements Visitor
{
public final Map<ParameterNode, ConstantNode> substitutions = new LinkedHashMap<ParameterNode, ConstantNode>();
@Override
public Visitable visit(Visitable node) throws StandardException {
if(node instanceof BinaryRelationalOperatorNode) {
BinaryRelationalOperatorNode bin = (BinaryRelationalOperatorNode)node;
if(bin.getRightOperand() instanceof ConstantNode) {
ConstantNode con = (ConstantNode)bin.getRightOperand();
ParameterNode param = new ParameterNode();
param.setNodeType(NodeTypes.PARAMETER_NODE);
param.init(substitutions.size(), null);
bin.setRightOperand(param);
substitutions.put(param, con);
}
}
return node;
}
@Override
public boolean visitChildrenFirst(Visitable node) {
return false;
}
@Override
public boolean stopTraversal() {
return false;
}
@Override
public boolean skipChildren(Visitable node) throws StandardException {
return false;
}
}
Raw
ParamerDemo.java
import com.foundationdb.sql.parser.ConstantNode;
import com.foundationdb.sql.parser.ParameterNode;
import com.foundationdb.sql.parser.SQLParser;
import com.foundationdb.sql.parser.StatementNode;
import com.foundationdb.sql.unparser.NodeToString;
import java.util.Map.Entry;
public class ParamerDemo
{
public static void main(String[] args) throws Exception {
SQLParser parser = new SQLParser();
for(String s : args) {
StatementNode stmt = parser.parseStatement(s);
Paramer paramer = new Paramer();
stmt.accept(paramer);
String post = new NodeToString().toString(stmt);
System.out.println(" pre: " + s);
System.out.println("post: " + post);
for(Entry<ParameterNode, ConstantNode> i : paramer.substitutions.entrySet()) {
System.out.printf(" $%d => %s (%s)\n",
i.getKey().getParameterNumber() + 1,
i.getValue().getValue(),
i.getValue().getValue().getClass().getSimpleName());
}
}
}
}
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