core

Documentation

Index

• func MakeComparisonScopeBuildFunc(columns ...string) ...
• func OrderClauseBuilder(columns ...string) func(orders ...Order) string
• type Comparison
• type CursorSegment
  • func (seg CursorSegment) Int64() int64
  • func (seg CursorSegment) Int64Ptr() *int64
  • func (seg CursorSegment) Interface(ty reflect.Type, column string) interface{}
  • func (seg CursorSegment) IsNil() bool
  • func (seg CursorSegment) Time() *time.Time
• type CursorSegments
  • func NewCursorSegments(str CursorString) CursorSegments
  • func (segs CursorSegments) Interface(ty reflect.Type, columns ...string) []interface{}
• type CursorString
  • func FormatCursorString(args ...interface{}) CursorString
  • func (cs CursorString) Validate() bool
• type Order
  • func ReverseOrders(orders []Order) []Order

Examples

• FormatCursorString
• NewCursorSegments
• OrderClauseBuilder
• ReverseOrders

Functions

func MakeComparisonScopeBuildFunc

func MakeComparisonScopeBuildFunc(columns ...string) func(comparisons ...Comparison) func(values ...interface{}) func(*gorm.DB) *gorm.DB

MakeComparisonScopeBuildFunc returns a GORM scope builder. This scope add a where clauses filtered by comparisons ranges.

func OrderClauseBuilder

func OrderClauseBuilder(columns ...string) func(orders ...Order) string

OrderClauseBuilder returns a function that create ORDER BY clause to specifies the order of DB records.

Example

fmt.Printf("%s\n", OrderClauseBuilder("ID", "CreatedAt")(ASC, ASC))
fmt.Printf("%s\n", OrderClauseBuilder("ID", "CreatedAt")(DESC, DESC))
fmt.Printf("%s\n", OrderClauseBuilder("ID", "CreatedAt")(ASC, DESC))

Output:

`id` ASC, `created_at` ASC
`id` DESC, `created_at` DESC
`id` ASC, `created_at` DESC

Types

type Comparison

type Comparison string

Comparison is a comparison operator used by where clause in SQL.

const (
	// GreaterThan means that the column value in DB record is greater than the specified value.
	GreaterThan Comparison = ">"
	// LessThan means that the column value in DB record is less than the specified value.
	LessThan Comparison = "<"
)

type CursorSegment

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

CursorSegment is a result of parsing each element of cursor.

func (CursorSegment) Int64

func (seg CursorSegment) Int64() int64

Int64 returns converted to integer.

func (CursorSegment) Int64Ptr

func (seg CursorSegment) Int64Ptr() *int64

Int64Ptr returns converted to pointer of integer.

func (CursorSegment) Interface

func (seg CursorSegment) Interface(ty reflect.Type, column string) interface{}

Interface returns converted to the type of the specified column.

func (CursorSegment) IsNil

func (seg CursorSegment) IsNil() bool

IsNil returns true if it have nil value. Otherwise, it returns false.

func (CursorSegment) Time

func (seg CursorSegment) Time() *time.Time

Time returns converted to time.

type CursorSegments

type CursorSegments []CursorSegment

CursorSegments is slice of CursorSegment.

func NewCursorSegments

func NewCursorSegments(str CursorString) CursorSegments

NewCursorSegments create a CursorSegments from CursorString,

Example

segments := NewCursorSegments("1585706584.025_20")
fmt.Println(segments[0].Time().UTC().String())
fmt.Println(segments[1].Int64())

Output:

2020-04-01 02:03:04.025 +0000 UTC
20

func (CursorSegments) Interface

func (segs CursorSegments) Interface(ty reflect.Type, columns ...string) []interface{}

Interface returns slice of interface that converted to types of specified columns.

type CursorString

type CursorString string

CursorString is a string indicating the Cursor.

func FormatCursorString

func FormatCursorString(args ...interface{}) CursorString

FormatCursorString returns a CursorString.

Example

format := "2006-01-02T15:04:05.9999"
ti, _ := time.Parse(format, "2020-04-01T02:03:04")

fmt.Println(FormatCursorString(ti, 1, 3.5))

Output:

1585706584_1_3

func (CursorString) Validate

func (cs CursorString) Validate() bool

Validate returns true, if it is valid. Otherwise, it returns false.

type Order

type Order string

Order is an ORDER BY clause specified in SQL, and represents the sort order.

const (
	// ASC is ascending, with the smallest values first.
	ASC Order = "asc"
	// DESC is descending, with the greatest values first.
	DESC Order = "desc"
)

func ReverseOrders

func ReverseOrders(orders []Order) []Order

ReverseOrders returns a slice of Order converted from ASC to DESC, DESC to ASC.

Example

fmt.Printf("%v\n", ReverseOrders([]Order{ASC, DESC, DESC}))
fmt.Printf("%v\n", ReverseOrders([]Order{DESC, ASC, ASC}))

Output:

[desc asc asc]
[asc desc desc]