MongoDB Operatoren

https://docs.mongodb.com/manual/reference/operator/

Abfrageoperatoren

db.collection_name.find({property_name: {$operator: value}})

Beispiele:

  • Studenten mit Semester < 3: db.student.find({semester: {$lt: 3}})
  • Studenten in einem der beiden Kurse "OMB" oder "MKB": db.student.find({course: {$in: ["OMB", "MKB"]}})

Operatoren:

  • $eq (equals), $lt (less than), $gt (greater than), $in (in)
  • kombiniert: $lte (less or equals), $gte (greater or equals)
  • negiert: $ne (not equals), $nin (not in)

mehr

Abfragen kombinieren

db.collection_name.find({ $kombinator: [JSONfind, JSONfind]})

Beispiele:

  • Student in OMB oder in Semester 6: db.student.find({ $or: [{course: "OMB"}, {semester: 6}]})
  • Student in OMB und Semester >= 2: db.student.find({ $and: [{course: "OMB"}, {semester: {$gte: 2}}]})
    • Alternativ: db.student.find({course:"OMB", semester: {$gte: 2}})

Operatoren:

  • $and (und Verbindung), $or (oder Verbindung)

mehr

Ergebnisse für Beispiele

db.student.find({semester: {$lt: 3}})

Kommandozeile> db.student.find({semester: {$lt: 3}})
{ "_id" : ObjectId("61a26b71293da259fc388bc4"), "studentNr" : 123456, "firstName" : "Klaus", "lastName" : "Meng", "semester" : 2, "faculty" : "DM", "course" : "OMB", "lecture_ids" : [ ObjectId("61a26eab293da259fc388bc9"), ObjectId("61a26eab293da259fc388bca") ] }
{ "_id" : ObjectId("61a26d0a293da259fc388bc6"), "studentNr" : 345678, "firstName" : "Samantha", "lastName" : "Holz", "semester" : 1, "faculty" : "DM", "course" : "OMB" }

db.student.find({course: {$in: ["OMB", "MKB"]}})

Kommandozeile> db.student.find({course: {$in: ["OMB", "MKB"]}})
{ "_id" : ObjectId("61a26b71293da259fc388bc4"), "studentNr" : 123456, "firstName" : "Klaus", "lastName" : "Meng", "semester" : 2, "faculty" : "DM", "course" : "OMB", "lecture_ids" : [ ObjectId("61a26eab293da259fc388bc9"), ObjectId("61a26eab293da259fc388bca") ] }
{ "_id" : ObjectId("61a26d0a293da259fc388bc6"), "studentNr" : 345678, "firstName" : "Samantha", "lastName" : "Holz", "semester" : 1, "faculty" : "DM", "course" : "OMB" }

db.student.find({ $or: [{course: "OMB"}, {semester: 6}]})

Kommandozeile> db.student.find({ $or: [{course: "OMB"}, {semester: 6}]})
{ "_id" : ObjectId("61a26b71293da259fc388bc4"), "studentNr" : 123456, "firstName" : "Klaus", "lastName" : "Meng", "semester" : 2, "faculty" : "DM", "course" : "OMB", "lecture_ids" : [ ObjectId("61a26eab293da259fc388bc9"), ObjectId("61a26eab293da259fc388bca") ] }
{ "_id" : ObjectId("61a26d0a293da259fc388bc5"), "studentNr" : 234567, "firstName" : "Verena", "lastName" : "Rist", "semester" : 6, "faculty" : "DM", "course" : "MIB" }
{ "_id" : ObjectId("61a26d0a293da259fc388bc6"), "studentNr" : 345678, "firstName" : "Samantha", "lastName" : "Holz", "semester" : 1, "faculty" : "DM", "course" : "OMB" }

db.student.find({ $and: [{course: "OMB"}, {semester: {$gte: 2}}]})

Kommandozeile> db.student.find({ $and: [{course: "OMB"}, {semester: {$gte: 2}}]})
{ "_id" : ObjectId("61a26b71293da259fc388bc4"), "studentNr" : 123456, "firstName" : "Klaus", "lastName" : "Meng", "semester" : 2, "faculty" : "DM", "course" : "OMB", "lecture_ids" : [ ObjectId("61a26eab293da259fc388bc9"), ObjectId("61a26eab293da259fc388bca") ] }

db.student.find({course:"OMB", semester: {$gte: 2}})

Kommandozeile> db.student.find({course:"OMB", semester: {$gte: 2}})
{ "_id" : ObjectId("61a26b71293da259fc388bc4"), "studentNr" : 123456, "firstName" : "Klaus", "lastName" : "Meng", "semester" : 2, "faculty" : "DM", "course" : "OMB", "lecture_ids" : [ ObjectId("61a26eab293da259fc388bc9"), ObjectId("61a26eab293da259fc388bca") ] }