CURD Operations

Create Data

add

Use add method to add a new record, return value is the id of inserted record:

export default class extends think.controller.base {
  async addAction(){
    let model = this.model("user");
    let insertId = await model.add({name: "xxx", pwd: "yyy"});
  }
}

addMany

Use addMany create many records:

export default class extends think.controller.base {
  async addAction(){
    let model = this.model("user");
    let insertId = await model.addMany([
      {name: "xxx", pwd: "yyy"},
      {name: "xxx1", pwd: "yyy1"}
    ]);
  }
}

thenAdd

We often need to prevent a field from duplication when designing database. So it's common to query whether data exists before inserting and just insert if it doesn't exist.

Model provides thenAdd to support this manipulation:

export default class extends think.controller.base {
  async addAction(){
    let model = this.model("user");
    //first param is the data need to add, second param is the condition, if there is no result when query use second param, the data will be added
    let result = await model.thenAdd({name: "xxx", pwd: "yyy"}, {name: "xxx"});
    // result returns {id: 1000, type: "add"} or {id: 1000, type: "exist"}
  }
}

Update Data

update

Use update method to update data, return value is the influenced records:

export default class extends think.controlle.base {
  async updateAction(){
    let model = this.model("user");
    let affectedRows = await model.where({name: "thinkjs"}).update({email: "admin@thinkjs.org"});
  }
}

increment

Use increment method to increase one field's value:

export default class extends think.model.base {
  updateViewNums(id){
    return this.where({id: id}).increment("view_nums", 1); // increase one to reading number
  }
}

decrement

Use decrement method to decrease one field's value:

export default class extends think.model.base {
  updateViewNums(id){
    return this.where({id: id}).decrement("coins", 10); // decrease ten coins
  }
}

Query Data

Model provides many ways to query data, you can: query one line data, query multiple lines data, read the field value, read max value, read results count and so on.

Query One Line Data

Use find to query one line data, return value is the object:

export default class extends think.controller.base {
  async listAction(){
    let model = this.model("user");
    let data = await model.where({name: "thinkjs"}).find();
    //data returns {name: "thinkjs", email: "admin@thinkjs.org", ...}
  }
}

If there doesn't exist the data you need, return value is blank object {}. You can use think.isEmpty to check whether it is blank.

Query Multiple Lines Data

Use select query many lines data, return value is results:

export default class extends think.controller.base {
  async listAction(){
    let model = this.model("user");
    let data = await model.limit(2).select();
    //data returns [{name: "thinkjs", email: "admin@thinkjs.org"}, ...]
  }
}

If there doesn't exist the data you need, return value is blank array []. You can use think.isEmpty to check whether it is blank.

Result Pagination

It's common to show paginated data in page. You need to query the total counts first, then calculate the number of pagination. Model provides countSelect method to facilitate this operation, it can query total counts automatically.

export default class extends think.controller.base {
  async listAction(){
    let model = this.model("user");
    let data = await model.page(this.get("page"), 10).countSelect();
  }
}

Return value's format:

{
  numsPerPage: 10, //number per page
  currentPage: 1, //current page
  count: 100, //total counts
  totalPages: 10, //total page number
  data: [{ //data of current page
    name: "thinkjs",
    email: "admin@thinkjs.org"
  }, ...]
}

If current page number exceeds page range, you can fix it through parameters. true means fix to first page, false means fix to last page: countSelect(true), countSelect(false).

If total count cannot be queried, you can pass it as a parameter like countSelect(1000), means total count is 1000.

count

Use count method to query total number of records that match the conditions:

export default class extends think.model.base {
  getCount(){
    // the total number where status = 'publish'
    return this.where({status: "publish"}).count();
  }
}

sum

Use sum method to compute the sum of values of the same fields that match the conditions:

export default class extends think.model.base {
  getSum(){
    // the sum of values of view_nums where status = 'publish'
    return this.where({status: "publish"}).sum("view_nums");
  }
}

max

Use max to find the largest value of the selected column:

export default class extends think.model.base {
  getMax(){
    // find the largest value of comments where status = 'publish'
    return this.where({status: "publish"}).max("comments");
  }
}

min

Use min to find the smallest value of the selected column:

export default class extends think.model.base {
  getMin(){
    // find the smallest value of comments where status = 'publish'
    return this.where({status: "publish"}).min("comments");
  }
}

Query Cache

Considering performance, querying data from cache is common. Doing it manually is difficult, so model provides cache method to set query cache:

export default class extends think.model.base {
  getList(){
    //set cache key and expire time
    return this.cache("get_list", 3600).where({id: {">": 100}}).select();
  }
}

These codes will cache query results. If cache matchs, results will be returned directly from cache. Otherwise, database will be used. The key of cache is get_list, will expire after one hour.

Key is optional, model will generate a cache key from sql command:

export default class extends think.model.base {
  getList(){
    //only set cache time
    return this.cache(3600).where({id: {">": 100}}).select();
  }
}

Cache Configuration

Config cache in model configuration's cache field:

export default {
  cache: {
    on: true,
    type: "", 
    timeout: 3600
  }
}

• on controls the whole database cache configurations, cache will be disabled if it is off
• type type of cache, default is memory, supported types can be found at Adapter -> Cache
• timeout default expire time

Delete Data

Use delete method to remove data, return the count of influenced row:

export default class extends think.controller.base {
  async deleteAction(){
    let model = this.model("user");
    let affectedRows = await model.where({id: [">", 100]}).delete();
  }
}

More operations in model can be found at API -> model.

This doc stays at https://github.com/75team/www.thinkjs.org/tree/master/view/zh-cn/doc/2.0/model_intro.md.