csvq

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 Go to latest Published: Nov 8, 2021 License: MIT Imports: 16 Imported by: 0

README

csvq driver

A go database/sql driver for csvq.

Build Status codecov

csvq-driver allows you to operate csv files and other supported formats using csvq statements in Go. You can use the statements in the same way as other relational database systems.

Reference Manual - csvq

Requirements

Go 1.14 or later (ref. Getting Started - The Go Programming Language)

Supported features

  • Query
    • Only the result-sets in the top-level scope can be retrieved. You cannot refer the results of child scopes such as inside of IF, WHILE and user-defined functions.
  • Exec
    • Only the last result in the top-level scope can be retrieved.
    • LastInsertId is not supported.
  • Prepared Statement
    • Ordinal placeholders
    • Named placeholders
  • Transaction
    • Isolation Level is the default only.
    • Read-only transaction is not supported.
    • If you do not use the database/sql transaction feature, all execusions will commit at the end of the execusion automatically.

Usage

Data Source Name

A data source name to call sql.Open is a directory path. It is the same as "--repository" option of the csvq command.

Some parameters can be specified in a DSN string with a directory path. A directory path and parameters are separated by a question mark, and parameters are separated by ampersands.

db, err := sql.Open("csvq", "/path/to/data/directory?Param1=Value&Param2=Value")
Parameters that can be specified
Name Type Default
Timezone string "Local"
DatetimeFormat string empty string
AnsiQuotes bool false

Parameter names are case-insensitive.

See: csvq > Reference Manual > Command Usage > Options

Error Handling

If a received error is a returned error from csvq, you can cast the error to github.com/mithrandie/csvq/lib/query.Error interface. The error interface has following functions.

function description
Message() string Error message
Code() int Error code. The same as the exit code of the csvq command
Number() int Error number
Line() int Line number where the error occurred in the passed statement
Char() int Column number where the error occurred in the passed statement
Source() string File or statement name where the error occurred
Example
package main

import (
	"context"
	"database/sql"
	"fmt"

	"github.com/mithrandie/csvq/lib/query"

	_ "github.com/mithrandie/csvq-driver"
)

func main() {
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	db, err := sql.Open("csvq", "/path/to/data/directory")
	if err != nil {
		panic(err)
	}
	defer func() {
		if err := db.Close(); err != nil {
			panic(err)
		}
	}()
	
	queryString := "SELECT id, first_name, country_code FROM `users.csv` WHERE id = '12'"
	r := db.QueryRowContext(ctx, queryString)

	var (
		id          int
		firstName   string
		countryCode string
	)

	if err := r.Scan(&id, &firstName, &countryCode); err != nil {
		if err == sql.ErrNoRows {
			fmt.Println("No Rows.")
		} else if csvqerr, ok := err.(query.Error); ok {
			panic(fmt.Sprintf("Unexpected error: Number: %d  Message: %s", csvqerr.Number(), csvqerr.Message()))
		} else {
			panic("Unexpected error: " + err.Error())
		}
	} else {
		fmt.Printf("Result: [id]%3d  [first_name]%10s  [country_code]%3s\n", id, firstName, countryCode)
	}
}

See: https://github.com/mithrandie/csvq-driver/blob/master/example/csvq-driver/csvq-driver-example.go

Replace I/O

You can replace input/output interface of the csvq to pass the data from inside of your go programs or retrive the result-sets as a another format.

function in the csvq-driver default description
SetStdin(r io.ReadCloser) error

SetStdinContext(ctx context.Context, r io.ReadCloser) error		 os.Stdin Replace input interface. Passed data can be refered as a temporary table named "STDIN".
SetStdout(w io.WriteCloser) query.Discard Replace output interface. Logs and result-sets of select queries are written to stdout.
SetOutFile(w io.Writer) nil Put a writer for result-sets of select queries to write instead of stdout.

The following structs are available for replacement.

struct name initializer
query.Input query.NewInput(r io.Reader)
query.Output query.NewOutput()

"query" means the package "github.com/mithrandie/csvq/lib/query".

See: https://github.com/mithrandie/csvq-driver/blob/master/example/replace-io/csvq-replace-io-example.go

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var DSNParseErr = errors.New("incorrect data source name")

Functions

func GenerateStatementName 

func GenerateStatementName() string

func IsCsvqValue 

func IsCsvqValue(v interface{}) bool

func NewCompositeError 

func NewCompositeError(errs []error) error

func NewStmt 

func NewStmt(ctx context.Context, proc *query.Processor, queryString string) (driver.Stmt, error)

func NewTx 

func NewTx(proc *query.Processor) (driver.Tx, error)

func SetOutFile 

func SetOutFile(w io.Writer)

func SetStdin 

func SetStdin(r io.ReadCloser) error

func SetStdinContext 

func SetStdinContext(ctx context.Context, r io.ReadCloser) error

func SetStdout 

func SetStdout(w io.WriteCloser)

Types

type Boolean 

type Boolean struct {
	// contains filtered or unexported fields
}

func (Boolean) PrimitiveType 

func (t Boolean) PrimitiveType() parser.PrimitiveType

func (Boolean) Value 

func (t Boolean) Value() (driver.Value, error)

type CompositeError 

type CompositeError struct {
	Errors []error
}

func (CompositeError) Error 

func (e CompositeError) Error() string

type Conn 

type Conn struct {
	// contains filtered or unexported fields
}

func NewConn 

func NewConn(ctx context.Context, dsnStr string, defaultWaitTimeout time.Duration, retryDelay time.Duration) (*Conn, error)

func (*Conn) Begin 

func (c *Conn) Begin() (driver.Tx, error)

func (*Conn) BeginTx 

func (c *Conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error)

func (*Conn) Close 

func (c *Conn) Close() error

func (*Conn) ExecContext 

func (c *Conn) ExecContext(ctx context.Context, queryString string, args []driver.NamedValue) (driver.Result, error)

func (*Conn) Prepare 

func (c *Conn) Prepare(queryString string) (driver.Stmt, error)

func (*Conn) PrepareContext 

func (c *Conn) PrepareContext(ctx context.Context, queryString string) (driver.Stmt, error)

func (*Conn) QueryContext 

func (c *Conn) QueryContext(ctx context.Context, queryString string, args []driver.NamedValue) (driver.Rows, error)

type Connector 

type Connector struct {
	// contains filtered or unexported fields
}

func (Connector) Connect 

func (t Connector) Connect(ctx context.Context) (driver.Conn, error)

func (Connector) Driver 

func (t Connector) Driver() driver.Driver

type DSN 

type DSN struct {
	// contains filtered or unexported fields
}

func ParseDSN 

func ParseDSN(dsnStr string) (DSN, error)

type Datetime 

type Datetime struct {
	// contains filtered or unexported fields
}

func (Datetime) PrimitiveType 

func (t Datetime) PrimitiveType() parser.PrimitiveType

func (Datetime) Value 

func (t Datetime) Value() (driver.Value, error)

type Driver 

type Driver struct {
}

func (Driver) Open 

func (d Driver) Open(dsn string) (driver.Conn, error)

func (Driver) OpenConnector 

func (d Driver) OpenConnector(dsn string) (driver.Connector, error)

func (Driver) OpenContext 

func (d Driver) OpenContext(ctx context.Context, dsn string) (driver.Conn, error)

type Float 

type Float struct {
	// contains filtered or unexported fields
}

func (Float) PrimitiveType 

func (t Float) PrimitiveType() parser.PrimitiveType

func (Float) Value 

func (t Float) Value() (driver.Value, error)

type Integer 

type Integer struct {
	// contains filtered or unexported fields
}

func (Integer) PrimitiveType 

func (t Integer) PrimitiveType() parser.PrimitiveType

func (Integer) Value 

func (t Integer) Value() (driver.Value, error)

type Null 

type Null struct {
}

func (Null) PrimitiveType 

func (t Null) PrimitiveType() parser.PrimitiveType

func (Null) Value 

func (t Null) Value() (driver.Value, error)

type Result 

type Result struct {
	// contains filtered or unexported fields
}

func NewResult 

func NewResult(rowsAffected int64) *Result

func (Result) LastInsertId 

func (r Result) LastInsertId() (int64, error)

func (Result) RowsAffected 

func (r Result) RowsAffected() (int64, error)

type Rows 

type Rows struct {
	// contains filtered or unexported fields
}

func NewRows 

func NewRows(selectedViews []*query.View) *Rows

func (*Rows) Close 

func (r *Rows) Close() error

func (*Rows) Columns 

func (r *Rows) Columns() []string

func (*Rows) HasNextResultSet 

func (r *Rows) HasNextResultSet() bool

func (*Rows) Next 

func (r *Rows) Next(dest []driver.Value) error

func (*Rows) NextResultSet 

func (r *Rows) NextResultSet() error

type Stmt 

type Stmt struct {
	// contains filtered or unexported fields
}

func (*Stmt) CheckNamedValue 

func (stmt *Stmt) CheckNamedValue(nv *driver.NamedValue) error

func (*Stmt) Close 

func (stmt *Stmt) Close() error

func (*Stmt) ColumnConverter 

func (stmt *Stmt) ColumnConverter(_ int) driver.ValueConverter

func (*Stmt) Exec 

func (stmt *Stmt) Exec(args []driver.Value) (driver.Result, error)

func (*Stmt) ExecContext 

func (stmt *Stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error)

func (*Stmt) NumInput 

func (stmt *Stmt) NumInput() int

func (*Stmt) Query 

func (stmt *Stmt) Query(args []driver.Value) (driver.Rows, error)

func (*Stmt) QueryContext 

func (stmt *Stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error)

type String 

type String struct {
	// contains filtered or unexported fields
}

func (String) PrimitiveType 

func (t String) PrimitiveType() parser.PrimitiveType

func (String) Value 

func (t String) Value() (driver.Value, error)

type Tx 

type Tx struct {
	// contains filtered or unexported fields
}

func (Tx) Commit 

func (tx Tx) Commit() error

func (Tx) Rollback 

func (tx Tx) Rollback() error

type Value 

type Value interface {
	Value() (driver.Value, error)
	PrimitiveType() parser.PrimitiveType
}

type ValueConverter 

type ValueConverter struct {
}

func (ValueConverter) ConvertValue 

func (c ValueConverter) ConvertValue(v interface{}) (driver.Value, error)

Source Files

View all Source files

Directories

Path Synopsis
csvq-driver
Usage: $ cd $GOPATH/src/github.com/mithrandie/csvq-driver $ go build ./example/csvq-driver/csvq-driver-example.go $ ./csvq-driver-example -r ./example/data
 Usage: $ cd $GOPATH/src/github.com/mithrandie/csvq-driver $ go build ./example/csvq-driver/csvq-driver-example.go $ ./csvq-driver-example -r ./example/data
replace-io
Usage: $ cd $GOPATH/src/github.com/mithrandie/csvq-driver $ go build ./example/csvq-driver/csvq-replace-io-example.go $ ./csvq-replace-io-example
 Usage: $ cd $GOPATH/src/github.com/mithrandie/csvq-driver $ go build ./example/csvq-driver/csvq-replace-io-example.go $ ./csvq-replace-io-example

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