protected void addUpdateWithJoins()

in empire-db/src/main/java/org/apache/empire/dbms/oracle/DBCommandOracle.java [292:372]
62 lines of code
13 McCabe index (conditional complexity)

    protected void addUpdateWithJoins(DBSQLBuilder sql, DBRowSet table)
    {
        // The update table
        DBColumn[] keyColumns = table.getKeyColumns();
        if (keyColumns==null || keyColumns.length==0)
            throw new NoPrimaryKeyException(table);
        // Generate Merge expression
        sql.reset(0);
        sql.append("MERGE INTO ");
        table.addSQL(sql, CTX_FULLNAME|CTX_ALIAS);
        // Using
        sql.append("\r\nUSING (");
        // Add set expressions
        List<DBColumnExpr> using = new ArrayList<DBColumnExpr>();
        // Add key columns
        for (DBColumn col : keyColumns)
            using.add(col);
        // Select Set-Expressions
        List<DBSetExpr> mergeSet = new ArrayList<DBSetExpr>(set.size());   
        for (DBSetExpr sex : set)
        {   // Select set expressions
            Object val = sex.getValue();
            if (val instanceof DBColumnExpr)
            {
                DBColumnExpr expr = ((DBColumnExpr)val);
                if (!(expr instanceof DBColumn) && !(expr instanceof DBAliasExpr))
                {   // rename column
                    String name = "COL_"+String.valueOf(mergeSet.size());
                    expr = expr.as(name);
                }
                // select
                using.add(expr);
                // Name
                DBValueExpr NAME_EXPR = getDatabase().getValueExpr("q0."+expr.getName(), DataType.UNKNOWN);
                mergeSet.add(sex.getColumn().to(NAME_EXPR));
            }
            else
            {   // add original
                mergeSet.add(sex);
            }
            // remove column from using list (if present)
            DBColumn setColum = sex.getColumn();
            if (using.contains(setColum))
                using.remove(setColum);
        }
        // Add select
        sql.append("SELECT ");
        // Add optimizer hint
        if (StringUtils.isNotEmpty(optimizerHint))
            sql.append("/*+ ").append(optimizerHint).append(" */ ");
        // Add select columns
        addListExpr(sql, using, CTX_ALL, ", ");
        // From clause
        addFrom(sql);
        // Add Where
        addWhere(sql);
        // Add Grouping
        addGrouping(sql);
        // on
        int count = 0;
        sql.append(") q0\r\nON (");
        for (DBColumn col : keyColumns)
        {   // skip set columns
            if (using.contains(col)==false)
                continue;
            // add separator 
            if (count++>0)
                sql.append(" AND ");
            // add constraint 
            sql.append(" q0.");
            col.addSQL(sql, CTX_NAME);
            sql.append("=");
            sql.append(table.getAlias());
            sql.append(".");
            col.addSQL(sql, CTX_NAME);
        }
        // Set Expressions
        sql.append(")\r\nWHEN MATCHED THEN UPDATE ");
        sql.append("\r\nSET ");
        addListExpr(sql, mergeSet, CTX_DEFAULT, ", ");
    }