db2中import的用法update

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参考技术A IMPORT的五种方式:
导入可使用五种方式,它们用于确定导入数据的方法。前三种方式为INSERT、INSERT_UPDATE和REPLACE,在目标表已存在的情况下使用。这三种方式都支持IXF、WSF、ASC和DEL数据格式。但是,只有INSERT和INSERT_UPDATE可与昵称配合使用。

UPDATE:使用输入行的值更新具有匹配主键值的行,如果没有匹配行,那么会将已导入行插入到表中。

MongoDB之update

Update操作只作用于集合中存在的文档。MongoDB提供了如下方法来更新集合中的文档:

  • db.collection.update()
  • db.collection.updateOne() New in version 3.2
  • db.collection.updateMany() New in version 3.2
  • db.collection.replaceOne() New in version 3.

你可以通过指定criteria或者filter来指定你想更新的文档:

 

update函数执行数据更新操作,该函数接受3个主要参数:criteria,action,options:

  • 参数criteria用于指定一个查询,查询选择将要更新的目标记录。
  • 参数action用于指定更新信息,也可以使用操作符来完成。
  • 参数options用于指定更新文档时的选项,可选值包括:upsert和multi。upsert可以指定如果数据存在就更新,不存在就创建数据;multi选项指定是否应该更新所有匹配的文档,或者只更新第一个文档(默认行为)。

为了更好的演示,插入数据:

db.users.insertMany(
   [
     {
       _id: 1,
       name: "sue",
       age: 19,
       type: 1,
       status: "P",
       favorites: { artist: "Picasso", food: "pizza" },
       finished: [ 17, 3 ],
       badges: [ "blue", "black" ],
       points: [
          { points: 85, bonus: 20 },
          { points: 85, bonus: 10 }
       ]
     },
     {
       _id: 2,
       name: "bob",
       age: 42,
       type: 1,
       status: "A",
       favorites: { artist: "Miro", food: "meringue" },
       finished: [ 11, 25 ],
       badges: [ "green" ],
       points: [
          { points: 85, bonus: 20 },
          { points: 64, bonus: 12 }
       ]
     },
     {
       _id: 3,
       name: "ahn",
       age: 22,
       type: 2,
       status: "A",
       favorites: { artist: "Cassatt", food: "cake" },
       finished: [ 6 ],
       badges: [ "blue", "Picasso" ],
       points: [
          { points: 81, bonus: 8 },
          { points: 55, bonus: 20 }
       ]
     },
     {
       _id: 4,
       name: "xi",
       age: 34,
       type: 2,
       status: "D",
       favorites: { artist: "Chagall", food: "chocolate" },
       finished: [ 5, 11 ],
       badges: [ "Picasso", "black" ],
       points: [
          { points: 53, bonus: 15 },
          { points: 51, bonus: 15 }
       ]
     },
     {
       _id: 5,
       name: "xyz",
       age: 23,
       type: 2,
       status: "D",
       favorites: { artist: "Noguchi", food: "nougat" },
       finished: [ 14, 6 ],
       badges: [ "orange" ],
       points: [
          { points: 71, bonus: 20 }
       ]
     },
     {
       _id: 6,
       name: "abc",
       age: 43,
       type: 1,
       status: "A",
       favorites: { food: "pizza", artist: "Picasso" },
       finished: [ 18, 12 ],
       badges: [ "black", "blue" ],
       points: [
          { points: 78, bonus: 8 },
          { points: 57, bonus: 7 }
       ]
     }
   ]
)

1. 字段更新操作符

1.1 覆盖更新

下面的例子使用update()函数执行更新数据操作,不包含操作符:

> db.users.find({"name":"xyz"});
{ "_id" : 5, "name" : "xyz", "age" : 23, "type" : 2, "status" : "D", "favorites" : { "artist" : "Noguchi", "food" : "nougat" }, "finished" : [ 14, 6 ], "badges" : [ "orange" ], "points" : [ { "points" : 71, "bonus" : 20 } ] }
>

修改之后:

> db.users.update({"name":"xyz"}, {name : "xyz", age:25, school : "xidian", type:1,  favorites: {artist : "Noguchi", food : "nougat"}, finished : [4, 5] }, {upsert:true});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> 
> 
> 
> db.users.find({"name":"xyz"});
{ "_id" : 5, "name" : "xyz", "age" : 25, "school" : "xidian", "type" : 1, "favorites" : { "artist" : "Noguchi", "food" : "nougat" }, "finished" : [ 4, 5 ] }

该例覆写了集合中的文档,并保存更新后的值。

备注

任何忽略的字段都被移除(文档被覆盖)

1.2 upsert

upsert可以指定如果数据存在就更新,不存在就创建数据。

> db.users.find({"name":"yoona"});
> 
> db.users.update({"name":"yoona"}, {name : "yoona", age:25, "school" : "xidian", type:1,  favorites: {artist : "Noguchi", food : "nougat"}, finished : [4, 5] }, {upsert:false});
WriteResult({ "nMatched" : 0, "nUpserted" : 0, "nModified" : 0 })

更新操作之前我们没有查询到yoona的任何信息,然后我们对其进行更新操作,并且upsert设置为false,表示如果更新的数据不存在,不走任何操作。更新之后,我们再次查询一下:

> db.users.find({"name":"yoona"});
>

再次查询还是没有找到相应数据。我们设置upsert为true,表示如果数据存在则更新,如果不存在则创建该数据:

> db.users.update({"name":"yoona"}, {name : "yoona", age:25, "school" : "xidian", type:1,  favorites: {artist : "Noguchi", food : "nougat"}, finished : [4, 5] }, {upsert:true});
WriteResult({
    "nMatched" : 0,
    "nUpserted" : 1,
    "nModified" : 0,
    "_id" : ObjectId("57c3ad26d2cc0133a95bc583")
})
> 
> db.users.find({"name":"yoona"});
{ "_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 25, "school" : "xidian", "type" : 1, "favorites" : { "artist" : "Noguchi", "food" : "nougat" }, "finished" : [ 4, 5 ] }

1.3 $inc 增加值

操作符$inc可以为指定的键执行(原子)更新操作,如果字段存在,就将该值增加给定的增量,如果该字段不存在,就创建该字段。

> db.users.update({"name":"yoona"}, {$inc:{age:2}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> 
> 
> db.users.find({name:"yoona"});
{ "_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "school" : "xidian", "type" : 1, "favorites" : { "artist" : "Noguchi", "food" : "nougat" }, "finished" : [ 4, 5 ] }

上面例子中将yoona用户的年龄增加两岁。

1.4 $set 设置字段值

可以使用$set操作符将某个字段设置为指定值。

> db.users.find({name:"yoona"});
{ "_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "school" : "xidian", "type" : 1, "favorites" : { "artist" : "Noguchi", "food" : "nougat" }, "finished" : [ 4, 5 ] }
> 
> db.users.update({"name":"yoona"}, {$set:{school:"Massachusetts Institute of Technology"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> 
> db.users.find({name:"yoona"});
{ "_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "school" : "Massachusetts Institute of Technology", "type" : 1, "favorites" : { "artist" : "Noguchi", "food" : "nougat" }, "finished" : [ 4, 5 ] }
>

上面例子将yoona用户的学校改为麻省理工学院。

1.5 $unset删除指定字段

> db.users.find({name:"yoona"});
{ "_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "school" : "Massachusetts Institute of Technology", "type" : 1, "favorites" : { "artist" : "Noguchi", "food" : "nougat" }, "finished" : [ 4, 5 ] }
> 
> db.users.update({"name":"yoona"}, {$unset:{school:"Massachusetts Institute of Technology"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> 
> db.users.find({name:"yoona"});
{ "_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "type" : 1, "favorites" : { "artist" : "Noguchi", "food" : "nougat" }, "finished" : [ 4, 5 ] }

上面例子将yoona用户的学校删除。

1.6 $rename 重命名字段名称

格式:

{$rename: { <field1>: <newName1>, <field2>: <newName2>, ... } }

新字段名称必须不同与已经存在的字段名称

> db.users.find({name:"yoona"});
{ "_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "name" : "yoona", "age" : 27, "type" : 1, "favorites" : { "artist" : "Noguchi", "food" : "nougat" }, "finished" : [ 4, 5 ] }
> 
> db.users.update({"name":"yoona"}, {$rename: {name:"userName", age:"userAge"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
>

查询:

> db.users.find({name:"yoona"});
> db.users.find({userName:"yoona"});
{ "_id" : ObjectId("57c3ad26d2cc0133a95bc583"), "type" : 1, "favorites" : { "artist" : "Noguchi", "food" : "nougat" }, "finished" : [ 4, 5 ], "userName" : "yoona", "userAge" : 27 }
>

上面例子中使用$rename将name改为userName,将age改为userAge。

1.7 $min $max数值比较

如果给定值(value1)小于字段的当前值,则更新字段值为给定值。$min运算符可以可以比较不同类型的数字。

格式:

{ $min: { <field1>: <value1>, ... } }

为了演示,添加如下数据:

> db.score.save({_id:1, highScore:90, lowScore: 50});
WriteResult({ "nMatched" : 0, "nUpserted" : 1, "nModified" : 0, "_id" : 1 })
> 
> 
> db.score.find();
{ "_id" : 1, "highScore" : 90, "lowScore" : 50 }

给定值与字段当前值进行比较,给定值10小于字段的当前值50,所以更新字段当前值为给定值10:

> db.score.update({_id:1}, {$min : {lowScore : 10}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> 
> db.score.find();
{ "_id" : 1, "highScore" : 90, "lowScore" : 10 }

给定值40大于字段当前值10,不做任何变化:

> db.score.update({_id:1}, {$min : {lowScore : 40}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 0 })
> 
> db.score.find();
{ "_id" : 1, "highScore" : 90, "lowScore" : 10 }
>

1.8 $setOnInsert

如果更新操作设置upsert:true,执行insert操作时,$setOnInsert会给给定字段赋值给定值。如果更新操作不会导致插入数据,$setOnInsert不会有任何作用。

格式:

db.collection.update(
   <query>,
   { $setOnInsert: { <field1>: <value1>, ... } },
   { upsert: true }
)

举例:

假设集合products中没有任何文档,进行如下操作:

> db.products.find();
> 
> db.products.update({_d:1}, {$set : {item : "apple"}, $setOnInsert : {defaultQty : 100}} , {upsert : true});
WriteResult({
    "nMatched" : 0,
    "nUpserted" : 1,
    "nModified" : 0,
    "_id" : ObjectId("57c43a0ebd7a19639b912212")
})
> 
> db.products.find();
{ "_id" : ObjectId("57c43a0ebd7a19639b912212"), "_d" : 1, "item" : "apple", "defaultQty" : 100 }

由于集合中没有任何文档,在对其字段item进行更新时,由于item字段不存在,执行insert操作时,触发setOnInsert操作符,给defaultQty字段赋值为100。

1.9 $currentDate

$curentDate设置字段值为当前日期,可以设置Date类型或者timestamp类型。

格式:

{ $currentDate: { <field1>: <typeSpecification1>, ... } }

为了演示,添加如下数据:

db.student.save({_id:1, name: "yoona", age: 24, college: "计算机学院"});

下面添加一个日期类型的"birthday"字段:

db.student.update({_id:1}, {$currentDate: {birthday: {$type: "date"}}});

最后输出结果:

{
    "_id" : 1.0,
    "name" : "yoona",
    "age" : 24.0,
    "college" : "计算机学院",
    "birthday" : ISODate("2016-08-30T02:29:24.425Z")
}

2. 数组操作符

2.1 $push 在指定字段中添加某个值

通过$push操作符可以在指定字段中添加某个值。如果该字段是个数组,那么该值将被添加到数组中。如果该字段尚不存在,那么该字段的值将被设置为数组。如果该字段存在,但不是数组,那么将会抛出异常。如果给定的值是个数组,那么该数组被看做是一个元素,添加给定字段中(If the value is an array, $push appends the whole array as a single element)。

格式:

{ $push: { <field1>: <value1>, ... } }

举例:

添加一个分数到成绩数组中:

db.student.update({_id:1}, {$push : {scores: 91}});

输出结果:

{
    "_id" : 1.0,
    "name" : "yoona",
    "age" : 24.0,
    "college" : "计算机学院",
    "birthday" : ISODate("2016-08-30T02:29:24.425Z"),
    "scores" : [ 
        89.0, 
        91.0
    ]
}

2.2 $push $each 指定数组中的多个值

格式:

{ $push: { <field>: { $each: [ <value1>, <value2> ... ] } } }

使用$push操作符可以将值添加到指定数组中,扩展指定元素中存储的数据。如果希望在给定的数组中添加多个值,可以使用可选的$each修改操作符。

db.student.update(
   { _id: 1 },
   { $push: { scores: { $each: [ 90, 92, 85 ] } } }
)

输出结果:

{
    "_id" : 1.0,
    "name" : "yoona",
    "age" : 24.0,
    "college" : "计算机学院",
    "birthday" : ISODate("2016-08-30T02:29:24.425Z"),
    "scores" : [ 
        89.0, 
        91.0, 
        90.0, 
        92.0, 
        85.0
    ]
}

在使用$each是还可以使用$slice修改操作符,通过这种方式可以限制$push操作符中数组内元素的数量。$slice可以是正数,负数或0。正数将保证数组中的前n个元素会被保留,使用负数将保证数组中的最后n个元素会被保留,而使用0则表示清空数组。注意:操作符$slice必须是$push操作中的第一个修改操作符。

使用0则表示清空数组:

db.student.update(
   { _id: 1 },
   { $push: { scores: { $each: [ 70, 78], $slice: 0 } } }
)

输出结果:

{
    "_id" : 1.0,
    "name" : "yoona",
    "age" : 24.0,
    "college" : "计算机学院",
    "birthday" : ISODate("2016-08-30T02:29:24.425Z"),
    "scores" : []
}

正数将保证数组中的前n个元素会被保留

db.student.update(
   { _id: 1 },
   { $push: { scores: { $each: [ 70, 78, 90], $slice: 2 } } }
)

输出结果:

{
    "_id" : 1.0,
    "name" : "yoona",
    "age" : 24.0,
    "college" : "计算机学院",
    "birthday" : ISODate("2016-08-30T02:29:24.425Z"),
    "scores" : [ 
        70.0, 
        78.0
    ]
}

使用负数将保证数组中的最后n个元素会被保留

db.student.update(
   { _id: 1 },
   { $push: { scores: { $each: [ 89, 56 ], $slice: -3 } } }
)

输出结果:

{
    "_id" : 1.0,
    "name" : "yoona",
    "age" : 24.0,
    "college" : "计算机学院",
    "birthday" : ISODate("2016-08-30T02:29:24.425Z"),
    "scores" : [ 
        78.0, 
        89.0, 
        56.0
    ]
}

操作符$each和$slice操作符保证不仅新值会被添加到数组中,还能保证吧数组的大小限制为指定值。

2.3 $sort 排序

db2 load选项

DB2db2命令Export与Import

db2 for update of的用法

db2 import export 到相同的 ixf 但不同的进程

db2数据库中update的一个简单用法:

DBeaver DB2 变量用法