insert.go

package dat

import (
	"bytes"
	"reflect"
)

// InsertBuilder contains the clauses for an INSERT statement
type InsertBuilder struct {
	Execer

	isInterpolated bool
	table          string
	cols           []string
	isBlacklist    bool
	vals           [][]interface{}
	records        []interface{}
	returnings     []string
}

// NewInsertBuilder creates a new InsertBuilder for the given table.
func NewInsertBuilder(table string) *InsertBuilder {
	if table == "" {
		logger.Error("InsertInto requires a table name.")
		return nil
	}
	return &InsertBuilder{table: table, isInterpolated: EnableInterpolation}
}

// Columns appends columns to insert in the statement
func (b *InsertBuilder) Columns(columns ...string) *InsertBuilder {
	return b.Whitelist(columns...)
}

// Blacklist defines a blacklist of columns and should only be used
// in conjunction with Record.
func (b *InsertBuilder) Blacklist(columns ...string) *InsertBuilder {
	b.isBlacklist = true
	b.cols = columns
	return b
}

// Whitelist defines a whitelist of columns to be inserted. To
// specify all columns of a record use "*".
func (b *InsertBuilder) Whitelist(columns ...string) *InsertBuilder {
	b.cols = columns
	return b
}

// Values appends a set of values to the statement
func (b *InsertBuilder) Values(vals ...interface{}) *InsertBuilder {
	b.vals = append(b.vals, vals)
	return b
}

// Record pulls in values to match Columns from the record
func (b *InsertBuilder) Record(record interface{}) *InsertBuilder {
	b.records = append(b.records, record)
	return b
}

// Returning sets the columns for the RETURNING clause
func (b *InsertBuilder) Returning(columns ...string) *InsertBuilder {
	b.returnings = columns
	return b
}

// Pair adds a key/value pair to the statement
func (b *InsertBuilder) Pair(column string, value interface{}) *InsertBuilder {
	b.cols = append(b.cols, column)
	lenVals := len(b.vals)
	if lenVals == 0 {
		args := []interface{}{value}
		b.vals = [][]interface{}{args}
	} else if lenVals == 1 {
		b.vals[0] = append(b.vals[0], value)
	} else {
		panic("pair only allows you to specify 1 record to insert")
	}
	return b
}

// ToSQL serialized the InsertBuilder to a SQL string
// It returns the string with placeholders and a slice of query arguments
func (b *InsertBuilder) ToSQL() (string, []interface{}) {
	if len(b.table) == 0 {
		panic("no table specified")
	}
	lenCols := len(b.cols)
	lenRecords := len(b.records)
	if lenCols == 0 {
		panic("no columns specified")
	}
	if len(b.vals) == 0 && lenRecords == 0 {
		panic("no values or records specified")
	}

	if lenRecords == 0 && b.cols[0] == "*" {
		panic(`"*" can only be used in conjunction with Record`)
	}

	if lenRecords == 0 && b.isBlacklist {
		panic(`Blacklist can only be used in conjunction with Record`)
	}

	// reflect fields removing blacklisted columns
	if lenRecords > 0 && b.isBlacklist {
		b.cols = reflectExcludeColumns(b.records[0], b.cols)
	}
	// reflect all fields
	if lenRecords > 0 && b.cols[0] == "*" {
		b.cols = reflectColumns(b.records[0])
	}

	var sql bytes.Buffer
	var args []interface{}

	sql.WriteString("INSERT INTO ")
	sql.WriteString(b.table)
	sql.WriteString(" (")

	for i, c := range b.cols {
		if i > 0 {
			sql.WriteRune(',')
		}
		Dialect.WriteIdentifier(&sql, c)
	}
	sql.WriteString(") VALUES ")

	start := 1
	// Go thru each value we want to insert. Write the placeholders, and collect args
	for i, row := range b.vals {
		if i > 0 {
			sql.WriteRune(',')
		}
		buildPlaceholders(&sql, start, len(row))

		for _, v := range row {
			args = append(args, v)
			start++
		}
	}
	anyVals := len(b.vals) > 0

	// Go thru the records. Write the placeholders, and do reflection on the records to extract args
	for i, rec := range b.records {
		if i > 0 || anyVals {
			sql.WriteRune(',')
		}

		ind := reflect.Indirect(reflect.ValueOf(rec))
		vals, err := valuesFor(ind.Type(), ind, b.cols)
		if err != nil {
			panic(err.Error())
		}
		buildPlaceholders(&sql, start, len(vals))
		for _, v := range vals {
			args = append(args, v)
			start++
		}
	}

	// Go thru the returning clauses
	for i, c := range b.returnings {
		if i == 0 {
			sql.WriteString(" RETURNING ")
		} else {
			sql.WriteRune(',')
		}
		Dialect.WriteIdentifier(&sql, c)
	}

	return sql.String(), args
}