Examples with QueryCompilation org.datanucleus.store.query.compiler.QueryCompilation used on opensource projects

Example 1 with QueryCompilation

use of org.datanucleus.store.query.compiler.QueryCompilation in project datanucleus-rdbms by datanucleus.

the class QueryToSQLMapper method processVariableExpression.

/* (non-Javadoc)
     * @see org.datanucleus.query.evaluator.AbstractExpressionEvaluator#processVariableExpression(org.datanucleus.query.expression.VariableExpression)
     */
@Override
protected Object processVariableExpression(VariableExpression expr) {
    String varName = expr.getId();
    Symbol varSym = expr.getSymbol();
    if (varSym != null) {
        // Use name from symbol if possible
        varName = varSym.getQualifiedName();
    }
    if (hasSQLTableMappingForAlias(varName)) {
        // Variable already found
        SQLTableMapping tblMapping = getSQLTableMappingForAlias(varName);
        SQLExpression sqlExpr = exprFactory.newExpression(tblMapping.table.getSQLStatement(), tblMapping.table, tblMapping.mapping);
        stack.push(sqlExpr);
        return sqlExpr;
    } else if (compilation.getCompilationForSubquery(varName) != null) {
        // Subquery variable
        QueryCompilation subCompilation = compilation.getCompilationForSubquery(varName);
        AbstractClassMetaData subCmd = ec.getMetaDataManager().getMetaDataForClass(subCompilation.getCandidateClass(), ec.getClassLoaderResolver());
        // Create subquery statement, using any provided alias if possible
        String subAlias = null;
        if (subCompilation.getCandidateAlias() != null && !subCompilation.getCandidateAlias().equals(candidateAlias)) {
            subAlias = subCompilation.getCandidateAlias();
        }
        StatementResultMapping subqueryResultMapping = new StatementResultMapping();
        // TODO Fix "avg(something)" arg - not essential but is a hack right now
        SQLStatement subStmt = RDBMSQueryUtils.getStatementForCandidates(storeMgr, stmt, subCmd, null, ec, subCompilation.getCandidateClass(), true, "avg(something)", subAlias, null, null);
        QueryToSQLMapper sqlMapper = new QueryToSQLMapper(subStmt, subCompilation, parameters, null, subqueryResultMapping, subCmd, true, fetchPlan, ec, importsDefinition, options, extensionsByName);
        sqlMapper.setDefaultJoinType(defaultJoinType);
        sqlMapper.setDefaultJoinTypeFilter(defaultJoinTypeFilter);
        sqlMapper.setParentMapper(this);
        sqlMapper.compile();
        if (subqueryResultMapping.getNumberOfResultExpressions() > 1) {
            throw new NucleusUserException("Number of result expressions in subquery should be 1");
        }
        SQLExpression subExpr = null;
        // TODO Cater for subquery select of its own candidate
        if (subqueryResultMapping.getNumberOfResultExpressions() == 0) {
            subExpr = new org.datanucleus.store.rdbms.sql.expression.SubqueryExpression(stmt, subStmt);
        } else {
            JavaTypeMapping subMapping = ((StatementMappingIndex) subqueryResultMapping.getMappingForResultExpression(0)).getMapping();
            if (subMapping instanceof TemporalMapping) {
                subExpr = new TemporalSubqueryExpression(stmt, subStmt);
            } else if (subMapping instanceof StringMapping) {
                subExpr = new StringSubqueryExpression(stmt, subStmt);
            } else {
                subExpr = new NumericSubqueryExpression(stmt, subStmt);
            }
            if (subExpr.getJavaTypeMapping() == null) {
                subExpr.setJavaTypeMapping(subMapping);
            }
        }
        stack.push(subExpr);
        return subExpr;
    } else if (stmt.getParentStatement() != null && parentMapper != null && parentMapper.candidateAlias != null && parentMapper.candidateAlias.equals(varName)) {
        // Variable in subquery linking back to parent query
        SQLExpression varExpr = exprFactory.newExpression(stmt.getParentStatement(), stmt.getParentStatement().getPrimaryTable(), stmt.getParentStatement().getPrimaryTable().getTable().getIdMapping());
        stack.push(varExpr);
        return varExpr;
    } else {
        // Variable never met before, so return as UnboundExpression - process later if needing binding
        NucleusLogger.QUERY.debug("QueryToSQL.processVariable (unbound) variable=" + varName + " is not yet bound so returning UnboundExpression");
        UnboundExpression unbExpr = new UnboundExpression(stmt, varName);
        stack.push(unbExpr);
        return unbExpr;
    }
}