DolphinDB

https://docs.dolphindb.cn/zh/
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DolphinDB is a high-performance time-series database that provides capabilities for data storage,...
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### Prepare environment for partition examples

Source: https://docs.dolphindb.cn/zh/pydoc/AdvancedOperations/ObjectOrientedOperationsOnDdbOBjects/Database.html

Imports required libraries and establishes a session connection. This setup is needed for the subsequent partition creation examples.

```python
**import** dolphindb **as** ddb
**import** dolphindb.settings **as** keys
**import** numpy **as** np
**import** pandas **as** pd

s = ddb.session()
s.connect("localhost", 8848, "admin", "123456")
```

--------------------------------

### Complete DolphinDB client example

Source: https://docs.dolphindb.cn/zh/godoc/go.html

Complete example of connecting to a DolphinDB server, running a script to get a schema, uploading a dictionary, and running a function. It demonstrates the typical workflow with error handling via panic.

```go
package main

import (
    "context"
    "fmt"

    "github.com/dolphindb/api-go/v3/api"
    "github.com/dolphindb/api-go/v3/model"
)

func main() {
    host := "ServerIP:Port"
    db, err := api.NewSimpleDolphinDBClient(context.TODO(), host, "userID", "passWord")
    if err != nil {
        // Handle err
        panic(err)
    }

    // run script on dolphindb server
    raw, err := db.RunScript("schema(tablename)")
    if err != nil {
        // Handle err
        panic(err)
    }

    // print the real dataform
    fmt.Println(raw.GetDataForm())

    // get the variable with real type
    dict := raw.(*model.Dictionary)
    fmt.Println(dict)

    // declare the specified variable ont the server
    _, err = db.Upload(map[string]model.DataForm{"dict": dict})
    if err != nil {
        // Handle err
        panic(err)
    }

    // run function on dolphindb server
    _, err = db.RunFunc("typestr", []model.DataForm{dict})
    if err != nil {
        // Handle err
        panic(err)
    }
}
```

--------------------------------

### BondFunctions::startDate example

Source: https://docs.dolphindb.cn/zh/plugins/quantlib/quantlib.html

Gets the start date of a bond. Constructs a fixed-rate bond with a semiannual schedule and calls startDate.

```dolphindb
use QuantLib
schedule = Schedule(2015.01.15, 2016.01.15, Period("Semiannual"), UnitedStates("NYSE"), 
              "Unadjusted", "Unadjusted", "Backward", false)
fixed_rate_bond = FixedRateBond(0, 100.0, schedule, [0.06], Thirty360("BondBasis"))
getBondFunctions().startDate(fixed_rate_bond)
```

--------------------------------

### Example coldVolumes configuration with local and S3 paths

Source: https://docs.dolphindb.cn/zh/db_distr_comp/db/tiered_storage.html

Example showing how to configure multiple coldVolumes paths, including a local path and an S3 path, using the <ALIAS> macro for per-node directories.

```text
coldVolumes=file://home/mypath/hdd/<ALIAS>,s3://bucket1/data/<ALIAS>
```

--------------------------------

### getInstrumentStart example with bond instrument

Source: https://docs.dolphindb.cn/zh/funcs/g/getinstrumentstart.html

Creates a bond dictionary, parses it with parseInstrument, and calls getInstrumentStart to get the start date. The output is 1996.03.01.

```dolphindb
bond = {
    "productType": "Cash",
    "assetType": "Bond",
    "bondType": "ZeroCouponBond",
    "instrumentId": "0001",
    "start": 1996.03.01,
    "maturity": 2032.05.15,
    "dayCountConvention": "ActualActualISDA",
    "coupon": 0.0276,
    "issuePrice": 100.0,
    "frequency": "Semiannual",
    "subType":"TREASURY_BOND",
    "creditRating":"B",
    "settlement": 2022.05.15 
}
ins = parseInstrument(bond)
getInstrumentStart(ins)
// output: 1996.03.01
```

--------------------------------

### SSEQuotationFile usage example

Source: https://docs.dolphindb.cn/zh/plugins/SSEQuotationFile.html

Complete example showing how to create a table, subscribe to a mktdt04.txt file, unsubscribe, get status, and get schemas for both supported file types.

```dolphindb
t = table(1:0, `SecurityID`Symbol`SymbolEn`TradeVolume`TotalValueTraded`PreClosePx`NominalPrice`HighPrice`LowPrice`TradePrice`BuyPrice1`BuyVolume1`SellPrice1`SellVolume1`SecTradingStatus`Timestamp, [SYMBOL, SYMBOL, SYMBOL,LONG, DOUBLE, DOUBLE, DOUBLE, DOUBLE, DOUBLE, DOUBLE, DOUBLE, LONG, DOUBLE, LONG, SYMBOL, TIME])
SSEQuotationFile::subscribe("mktdt04.txt", "/home/luzhouzheng/code/lzz/bin/mktdt04.txt", t)

SSEQuotationFile::unsubscribe("mktdt04.txt")

SSEQuotationFile::getStatus()

SSEQuotationFile::getSchema("mktdt04.txt", true)
SSEQuotationFile::getSchema("csiYYYYMMDD.txt", true)
```

--------------------------------

### 配置启动脚本路径

Source: https://docs.dolphindb.cn/zh/tutorials/Startup.html

在配置文件中设置 startup 参数，指定启动脚本文件路径。支持绝对路径或相对路径。

```配置文件
startup=/home/streamtest/init/server/startup.dos
```

--------------------------------

### Example 1: Define matching engine parameters with custom function

Source: https://docs.dolphindb.cn/zh/plugins/matchingEngineSimulator/mes.html

Logs in, loads the plugin, and defines order type and direction constants. This is the beginning of an example that sets up parameters for the matching engine.

```dolphindb
login("admin", "123456") // 登录
try{
    loadPlugin("MatchingEngineSimulator") // 加载插件
}catch(ex){
}
go

// 定义订单类型和方向常量
MARKET_BEST_FIVE = 0
MARKET_INSTANT_DEAL = 1
MARKET_THIS_BEST = 2
MARKET_OTHER_BEST = 3
MARKET_ALL_DEAL = 4
LIMIT_ORDER = 5
```

--------------------------------

### Get a row from BasicArrayVector using get

Source: https://docs.dolphindb.cn/zh/javadoc/data_types_and_forms/dataforms.html

Retrieves a specific row from a BasicArrayVector using the get method. The example gets index 2 and prints the resulting vector.

```java
List<Vector> list = new ArrayList<>();
list.add(new BasicIntVector(new int[]{1,2,3}));
list.add(new BasicIntVector(new int[]{4,5}));
list.add(new BasicIntVector(new int[]{6,7,8}));
list.add(new BasicIntVector(new int[]{9,10}));

Vector vector = (Vector) arrayVector.get(2);
System.out.println(vector.getString());

// output:
[6,7,8]
```

--------------------------------

### getMemId example

Source: https://docs.dolphindb.cn/zh/plugins/kafka/kafka.html

Example showing how to get the consumer's member ID after subscribing and polling.

```dolphindb
consumerCfg = dict(STRING, ANY)
consumerCfg["group.id"] = string(now())
consumerCfg["metadata.broker.list"] = "localhost:9092";
consumer = kafka::consumer(consumerCfg)
kafka::subscribe(consumer, "test");
kafka::consumerPoll(consumer); // 因为如果不进行数据的拉取，可能在 Kafka 集群端不会被分配对应 ID
kafka::getMemId(consumer)
// output: 'rdkafka-d9eded44-358f-49fc-be01-cc099b121d59'
```

--------------------------------

### settings.txt 定义数据文件路径

Source: https://docs.dolphindb.cn/zh/tutorials/unit_testing.html

在 setup 目录下的 settings.txt 文件中定义测试用例使用的数据文件路径，供多个测试文件共享。

```plaintext
DATA_DIR = "/home/xfhang/dolphindbmodules/ta/test/setup/data"
```

--------------------------------

### Install amdQuote plugin with installPlugin

Source: https://docs.dolphindb.cn/zh/plugins/amdquote/amdquote_2.html

Installs the amdQuote plugin for a specific AMD SDK version. The example installs amdQuote401 for AMD SDK 4.0.1.

```dolphindb
installPlugin("amdQuote401")
```

--------------------------------

### Create a partitioned table for sample example

Source: https://docs.dolphindb.cn/zh/progr/sql/sample.html

Creates a table with 1,000,000 rows, defines a range-partitioned database, and creates and populates a partitioned table 'pt' with 5 partitions.

```dolphindb
n=1000000
ID=rand(50, n)
x=rand(1.0, n)
t=table(ID, x)
db=database("dfs://rangedb1", RANGE, 0 10 20 30 40 50)
pt = db.createPartitionedTable(t, `pt, `ID)
pt.append!(t)
pt=loadTable(db,`pt);
```

--------------------------------

### Start Nginx and verify configuration

Source: https://docs.dolphindb.cn/zh/tutorials/nginx_dolphindb.html

Starts Nginx as a daemon and checks the configuration file syntax with -t. A successful check outputs 'syntax is ok' and 'test is successful'; then visiting the node's IP (e.g., http://192.168.1.20/) should show the default welcome page.

```bash
/usr/local/webserver/nginx/sbin/nginx 
```

```bash
/usr/local/webserver/nginx/sbin/nginx -t 
```

--------------------------------

### py::type example

Source: https://docs.dolphindb.cn/zh/plugins/py/py_3_9.html

Example of using py::type to get the class of a string and a date object.

```dolphindb
os = py::import("os");
cwd = os.getcwd();
py::type(cwd);
// Output: <class 'str'>

datetime = py::import("datetime");
dt = datetime.date.today();
py::type(dt);
// Output: <class 'datetime.date'>
```

--------------------------------

### BondFunctions::accrualStartDate example

Source: https://docs.dolphindb.cn/zh/plugins/quantlib/quantlib.html

Creates a fixed-rate bond and calls accrualStartDate. Note: the example omits the 'use QuantLib' and evaluation date setup seen in other examples.

```dolphindb
schedule = Schedule(2015.01.15, 2016.01.15, Period("Semiannual"), UnitedStates("NYSE"), 
              "Unadjusted", "Unadjusted", "Backward", false)
fixed_rate_bond = FixedRateBond(0, 100.0, schedule, [0.06], Thirty360("BondBasis"))
getBondFunctions().accrualStartDate(fixed_rate_bond)
```

--------------------------------

### Example: create database and table, then add column

Source: https://docs.dolphindb.cn/zh/progr/sql/alter.html

Creates a database and table, loads the table, adds a column 'location', and displays the schema. The output shows the new column appended.

```dolphindb
if(existsDatabase("dfs://test")) dropDatabase("dfs://test")
create database "dfs://test" partitioned by VALUE(1..10), HASH([SYMBOL, 40]), engine='OLAP', atomic='TRANS', chunkGranularity='TABLE'

create table "dfs://test"."pt"(
        id INT,
        deviceId SYMBOL,
        date DATE[comment="time_col", compress="delta"],
        value DOUBLE,
        isFin BOOL
    )
partitioned by ID, deviceID

pt = loadTable("dfs://test", `pt)
alter table pt add location SYMBOL;
pt = loadTable("dfs://test", `pt)
pt.schema().colDefs
```

--------------------------------

### connect example

Source: https://docs.dolphindb.cn/zh/plugins/opc/opc.html

Example connection to a Matrikon OPC simulation server with update rate 100 ms.

```dolphindb
connection=connect(`127.0.0.1,`Matrikon.OPC.Simulation.1,100)
```

--------------------------------

### GetDataFormString usage example

Source: https://docs.dolphindb.cn/zh/godoc/go.html

Example usage of GetDataFormString to get the string representation of the DfTable data form and print it.

```go
dfs := model.GetDataFormString(model.DfTable)
fmt.Println(dfs)
```

--------------------------------

### startup.dos 自动订阅 NSQ 行情

Source: https://docs.dolphindb.cn/zh/modules/easyNSQ/easynsq.html

在 startup.dos 中登录数据库、加载 nsq 插件、调用 easyNSQ 模块，并订阅沪深市场的 orders、trade、snapshot 数据，持久化存储。

```dos
// 登录数据库
login(`admin, `123456)
go
// 加载插件
try{ loadPlugin("nsq") } catch(ex) { print(ex) }
go
// 调用模块
use DolphinDBModules::easyNSQ
go

configFilePath = "<your_path_to>/nsq_sdk_config.ini";

// 初始化环境(不删除分区表)
iniNsqEnv()

// 拉起订阅
subscribeNsq(configFilePath, "orders", ["sh","sz"], saveToDfs=true)
subscribeNsq(configFilePath, "trade", ["sh","sz"], saveToDfs=true)
subscribeNsq(configFilePath, "snapshot", ["sh","sz"], saveToDfs=true)
```

--------------------------------

### GetDataTypeString usage example

Source: https://docs.dolphindb.cn/zh/godoc/go.html

Example usage of GetDataTypeString to get the string representation of the DtString data type and print it.

```go
dts := model.GetDataTypeString(model.DtString)
fmt.Println(dts)
```

--------------------------------

### Configure coldVolumes for tiered storage example

Source: https://docs.dolphindb.cn/zh/db_distr_comp/db/tiered_storage.html

Assumed configuration for the usage example, setting a local path for cold data storage.

```text
coldVolumes=file://home/dolphindb/tiered_store/<ALIAS>
```

--------------------------------

### listPluginsByCluster example

Source: https://docs.dolphindb.cn/zh/funcs/l/listPluginsByCluster.html

Shows how to use listPluginsByCluster on the MoM cluster to query plugin installations on the MoMSender cluster. The example first installs and loads the mysql plugin on MoMSender nodes, then calls listPluginsByCluster("MoMSender") on the MoM cluster.

```dolphindb
// MoMSender 集群节点:
installPlugin("mysql")
loadPlugin("mysql")
  
// MoM 集群:
listPluginsByCluster("MoMSender")
  

```

--------------------------------

### Optimized query example with [HINT_EXPLAIN]

Source: https://docs.dolphindb.cn/zh/progr/sql/hint_explain.html

Example of a query on a partitioned table that gets optimized, showing the optimize tag in the execution plan.

```sql
select [HINT_EXPLAIN] * from t1 where date = 2022.01.01
```

--------------------------------

### List interfaces of example package

Source: https://docs.dolphindb.cn/zh/plugins/py/py_3_9.html

Displays the available classes and functions in the example module using py::dir.

```dolphindb
py::dir(example)
// 示例输出（string 向量）：
// Example	__builtins__ ... __name__ __package__ __spec__ myFunc
```

--------------------------------

### Complete dictUpdate! example

Source: https://docs.dolphindb.cn/zh/tutorials/func_progr_cases.html

Complete example that creates the orders table, initializes the dictionary, and updates it with dictUpdate!.

```dolphindb
orders = table(`IBM`IBM`IBM`GOOG as SecID, 1 2 3 4 as Value, 4 5 6 7 as Vol)
historyDict = dict(STRING, ANY)
historyDict.dictUpdate!(function=def(x,y){tableInsert(x,y);return x}, keys=orders.SecID, parameters=orders,
            initFunc=def(x){t = table(100:0, x.keys(), each(type, x.values())); tableInsert(t, x); return t})
```

--------------------------------

### Unzip DolphinDB installation package

Source: https://docs.dolphindb.cn/zh/omc/omc/omc_ha_cluster_deploy.html

Extracts the DolphinDB installation package to the /DolphinDB directory. The installation path must not contain spaces or Chinese characters, otherwise starting data nodes will fail.

```shell
unzip DolphinDB_Linux64_V2.00.9.1.zip -d /DolphinDB
```

--------------------------------

### Usage example: get schema

Source: https://docs.dolphindb.cn/zh/plugins/ctp.html

Retrieves the schema for marketData.

```dolphindb
schema = ctp::getSchema(handle, `marketData)
```

--------------------------------

### Create and backup sample databases

Source: https://docs.dolphindb.cn/zh/funcs/m/migrate.html

Creates two databases (dfs://db1 and dfs://db2) with tables, then backs them up to the same directory using the backup function. This setup is required for the subsequent migrate examples.

```DolphinDB
backupDir="/home/DolphinDB/backup"

n = 1000000
t1 = table(rand(2012.12.01..2012.12.10, n) as date, rand(`AAPL`IBM`GOOG`MSFT, n) as sym, rand(1000.0,n) as price)
t2 = table(rand(2012.12.01..2012.12.10, n) as date, rand(`AAPL`IBM`GOOG`MSFT, n) as sym, rand(1000,n) as qty)
db1 = database(directory="dfs://db1", partitionType=VALUE, partitionScheme=2012.12.01..2012.12.10)
trades1 = db1.createPartitionedTable(t1, `trades1, `date).append!(t1)
trades2 = db1.createPartitionedTable(t2, `trades2, `date).append!(t2)

n = 1000000
t1 = table(rand(2012.12.01..2012.12.10, n) as date, rand(`AAPL`IBM`GOOG`MSFT, n) as sym, rand(1000.0,n) as price)
t2 = table(rand(2012.12.01..2012.12.10, n) as date, rand(`AAPL`IBM`GOOG`MSFT, n) as sym, rand(1000,n) as qty)
db1 = database(directory="dfs://db2", partitionType=VALUE, partitionScheme=`AAPL`IBM`GOOG`MSFT)
quotes1 = db1.createPartitionedTable(t1, `quotes1, `sym).append!(t1)
quotes2 = db1.createPartitionedTable(t2, `quotes2, `sym).append!(t2)

backup(backupDir=backupDir, sqlObj=<select * from trades1>, force=true)
backup(backupDir=backupDir, sqlObj=<select * from trades2>, force=true)
backup(backupDir=backupDir, sqlObj=<select * from quotes1>, force=true)
backup(backupDir=backupDir, sqlObj=<select * from quotes2>, force=true)
```

--------------------------------

### showTables example

Source: https://docs.dolphindb.cn/zh/plugins/hbase/hbase.html

Example of connecting and showing tables.

```dolphindb
conn = hbase::connect("192.168.1.114", 9090)
hbase::showTables(conn)
```

--------------------------------

### kdb::extractTableSchema example

Source: https://docs.dolphindb.cn/zh/plugins/kdb/kdb.html

Example of using kdb::extractTableSchema to get the schema of a kdb+ table file. The result is stored in the variable shcema.

```dolphindb
DATA_DIR="/path/to/data/kdb_sample"
shcema = kdb::extractTableSchema(handle, DATA_DIR + "/2022.06.17/Txns")
```

--------------------------------

### Create database and partitioned table via API

Source: https://docs.dolphindb.cn/zh/godoc/go.html

Creates a database and a partitioned table on the DolphinDB server. Steps: init client, init database request, create database, init create partitioned table request, create partitioned table. Uses NewSimpleDolphinDBClient for client initialization.

```go
package main

import (
    "context"

    "github.com/dolphindb/api-go/v3/api"
)

func main() {
    // step 1: init Dolphindb client
    host := "ServerIP:Port"
    db, err := api.NewSimpleDolphinDBClient(context.TODO(), host, "userID", "passWord")
    if err != nil {
        // Handle err
        panic(err)
    }

    // step 2: init create database request
    dbReq := &api.DatabaseRequest{
        Directory:       "dfs://db1",
        PartitionType:   "VALUE",
        PartitionScheme: "1..10",
        DBHandle:        "example",
    }

    // step 3: create database
    dt, err := db.Database(dbReq)
    if err != nil {
        // Handle err
        panic(err)
    }

    // step 4: init create partitioned table request
    createReq := &api.CreatePartitionedTableRequest{
        SrcTable:             "sourceTable",
        PartitionedTableName: "tableName",
        PartitionColumns:     []string{"id"},
    }

    // step 5: create partitioned table with database handler
    _, err = dt.CreatePartitionedTable(createReq)
    if err != nil {
        // Handle err
        panic(err)
    }
}
```
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