/*
* JsonSQL var _f1_obj = jsonsql.query("select id,mc,fid from json where (fid==475 && id==875 || fid==475)", json);
*/
var jsonsql =
{
query: function (sql, json) {
var returnfields = sql.match(/^(select)\s+([a-z0-9_\,\.\s\*]+)\s+from\s+([a-z0-9_\.]+)(?: where\s+\((.+)\))?\s*(?:order\sby\s+([a-z0-9_\,]+))?\s*(asc|desc|ascnum|descnum)?\s*(?:limit\s+([0-9_\,]+))?/
i);
var ops =
{
fields: returnfields[2].replace(' ', '').split(','
),
from: returnfields[3].replace(' ', ''
),
where: (returnfields[4] == undefined) ? "true" : returnfields[4
],
orderby: (returnfields[5] == undefined) ? [] : returnfields[5].replace(' ', '').split(','
),
order: (returnfields[6] == undefined) ? "asc" : returnfields[6
],
limit: (returnfields[7] == undefined) ? [] : returnfields[7].replace(' ', '').split(','
)
};
return this.parse(json, ops);
},
parse: function (json, ops) {
var o = { fields: ["*"], from: "json", where: "", orderby: [], order: "asc"
, limit: [] };
for (i
in ops) o[i] =
ops[i];
var result =
[];
result =
this.returnFilter(json, o);
result =
this.returnOrderBy(result, o.orderby, o.order);
result =
this.returnLimit(result, o.limit);
return result;
},
returnFilter: function (json, jsonsql_o) {
var jsonsql_scope =
eval(jsonsql_o.from);
var jsonsql_result =
[];
var jsonsql_rc = 0
;
if (jsonsql_o.where == ""
)
jsonsql_o.where = "true"
;
for (
var jsonsql_i
in jsonsql_scope) {
with (jsonsql_scope[jsonsql_i]) {
if (eval(jsonsql_o.where)) {
jsonsql_result[jsonsql_rc++] =
this.returnFields(jsonsql_scope[jsonsql_i], jsonsql_o.fields);
}
}
}
return jsonsql_result;
},
returnFields: function (scope, fields) {
if (fields.length == 0
)
fields = ["*"
];
if (fields[0] == "*"
)
return scope;
var returnobj =
{};
for (
var i
in fields)
returnobj[fields[i]] =
scope[fields[i]];
return returnobj;
},
returnOrderBy: function (result, orderby, order) {
if (orderby.length == 0
)
return result;
result.sort(function (a, b) {
switch (order.toLowerCase()) {
case "desc":
return (eval('a.' + orderby[0] + ' < b.' + orderby[0])) ? 1 : -1
;
case "asc":
return (eval('a.' + orderby[0] + ' > b.' + orderby[0])) ? 1 : -1
;
case "descnum":
return (eval('a.' + orderby[0] + ' - b.' + orderby[0
]));
case "ascnum":
return (eval('b.' + orderby[0] + ' - a.' + orderby[0
]));
}
});
return result;
},
returnLimit: function (result, limit) {
switch (limit.length) {
case 0:
return result;
case 1:
return result.splice(0, limit[0
]);
case 2:
return result.splice(limit[0] - 1, limit[1
]);
}
}
};
转载于:https://www.cnblogs.com/daixingqing/archive/2013/04/11/3014948.html
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