writefreely/db/alter.go

53 lines
1.2 KiB
Go

package db
import (
"fmt"
"strings"
)
type AlterTableSqlBuilder struct {
Dialect DialectType
Name string
Changes []string
}
func (b *AlterTableSqlBuilder) AddColumn(col *Column) *AlterTableSqlBuilder {
if colVal, err := col.String(); err == nil {
b.Changes = append(b.Changes, fmt.Sprintf("ADD COLUMN %s", colVal))
}
return b
}
func (b *AlterTableSqlBuilder) ChangeColumn(name string, col *Column) *AlterTableSqlBuilder {
if colVal, err := col.String(); err == nil {
b.Changes = append(b.Changes, fmt.Sprintf("CHANGE COLUMN %s %s", name, colVal))
}
return b
}
func (b *AlterTableSqlBuilder) AddUniqueConstraint(name string, columns ...string) *AlterTableSqlBuilder {
b.Changes = append(b.Changes, fmt.Sprintf("ADD CONSTRAINT %s UNIQUE (%s)", name, strings.Join(columns, ", ")))
return b
}
func (b *AlterTableSqlBuilder) ToSQL() (string, error) {
var str strings.Builder
str.WriteString("ALTER TABLE ")
str.WriteString(b.Name)
str.WriteString(" ")
if len(b.Changes) == 0 {
return "", fmt.Errorf("no changes provide for table: %s", b.Name)
}
changeCount := len(b.Changes)
for i, thing := range b.Changes {
str.WriteString(thing)
if i < changeCount-1 {
str.WriteString(", ")
}
}
return str.String(), nil
}