ArangoDB-如何通过数组元素的子字符串在集合中查找元素?
有一个具有此结构的集合:ArangoDB-如何通过数组元素的子字符串在集合中查找元素?,arangodb,aql,Arangodb,Aql,有一个具有此结构的集合: { "user": 1, "timestamp": 216354113151, "message": "asddsaasddsaa", "data": [ "name = Jack & hash = s5w464t35w145df13s5df4sdg & id = 2" "name = Mansonack & hash = xga5fd7h68745v46ed2 & id = 18"
{
"user": 1,
"timestamp": 216354113151,
"message": "asddsaasddsaa",
"data": [
"name = Jack & hash = s5w464t35w145df13s5df4sdg & id = 2"
"name = Mansonack & hash = xga5fd7h68745v46ed2 & id = 18"
]
}
我需要找到这个集合的一个元素,在key data中有一个值,该值包含一个字符串,该字符串包含子字符串xga5fd7h68745v46ed2
我可以写这个查询吗?它看起来如何?您可以像在任何其他列表上一样循环数组项:
FOR d IN collection_name
FILTER IS_LIST(d.data)
FOR data IN d.data
FILTER CONTAINS(data, "xga5fd7h68745v46ed2")
RETURN d
如果您的数据数组有多个正在搜索的子字符串,并且只希望返回包含搜索值的唯一文档,请使用如下查询:
// what you are looking for in string
LET searchValue = 'xga5fd7h68745v46ed2'
// go through items of your collection
FOR item IN collection_name
// store result of subquery in temporary variable
LET wasItemFound = FIRST((
// go through elements of your data array
FOR str IN item.data
// search for desired value within the element
FILTER CONTAINS(str, searchValue)
// we need to find only single occurance of searchValue
LIMIT 1
// return true if it was found
RETURN true
))
// give me only items which contained value you searched for
FILTER wasItemFound == true
RETURN item
如果您要查找的值对于所有数据数组元素都是唯一的,那么查询pluma建议哪个可以为您的用例执行此任务。如果在数据数组元素中搜索的子字符串多次出现,则查询将返回重复的文档。例如,考虑这个示例数据集:
[
{
"user": 1,
"data": [
"name = Jack & hash = abc & id = 2",
"name = Mansonack & hash = abcd & id = 18"
]
},
{
"user": 2,
"data": [
"name = Jack & hash = abb & id = 2",
"name = Mansonack & hash = abc & id = 18",
"name = xxx& hash = aaa & id = 18"
]
}
]
如果使用此查询
FOR d IN collection_name
FILTER IS_LIST(d.data)
FOR data IN d.data
FILTER CONTAINS(data, "ab")
RETURN d
即使集合仅包含2个文档,它也将返回4个文档。然而,本文中的第一个查询将只返回2。说清楚一点,我并不是说普卢马的解决方案是错误的,它只是取决于你希望得到什么回报