repo_description: SQL-first Golang ORM
repo_topics: database go golang mssql mysql oracle orm postgresql sql sqlite sqlite3
code: package bun
  
  import (
  	"context"
  	"database/sql"
  
  	"github.com/uptrace/bun/dialect/feature"
  	"github.com/uptrace/bun/internal"
  	"github.com/uptrace/bun/schema"
  )
  
  // TruncateTableQuery builds TRUNCATE TABLE statements.
  type TruncateTableQuery struct {
  	baseQuery
  	cascadeQuery
  
  	continueIdentity bool
  	comment          string
  }
  
  var _ Query = (*TruncateTableQuery)(nil)
  
  // NewTruncateTableQuery creates a TruncateTableQuery attached to the given DB.
  func NewTruncateTableQuery(db *DB) *TruncateTableQuery {
  	q := &TruncateTableQuery{
  		baseQuery: baseQuery{
  			db: db,
  		},
  	}
  	return q
  }
  
  func (q *TruncateTableQuery) Conn(db IConn) *TruncateTableQuery {
  	q.setConn(db)
  	return q
  }
  
  func (q *TruncateTableQuery) Model(model any) *TruncateTableQuery {
  	q.setModel(model)
  	return q
  }
  
  func (q *TruncateTableQuery) Err(err error) *TruncateTableQuery {
  	q.setErr(err)
  	return q
  }
  
  //------------------------------------------------------------------------------
  
  func (q *TruncateTableQuery) Table(tables ...string) *TruncateTableQuery {
  	for _, table := range tables {
  		q.addTable(schema.UnsafeIdent(table))
  	}
  	return q
  }
  
  func (q *TruncateTableQuery) TableExpr(query string, args ...any) *TruncateTableQuery {
  	q.addTable(schema.SafeQuery(query, args))
  	return q
  }
  
  func (q *TruncateTableQuery) ModelTableExpr(query string, args ...any) *TruncateTableQuery {
  	q.modelTableName = schema.SafeQuery(query, args)
  	return q
  }
  
  //------------------------------------------------------------------------------
  
  func (q *TruncateTableQuery) ContinueIdentity() *TruncateTableQuery {
  	q.continueIdentity = true
  	return q
  }
  
  func (q *TruncateTableQuery) Cascade() *TruncateTableQuery {
  	q.cascade = true
  	return q
  }
  
  func (q *TruncateTableQuery) Restrict() *TruncateTableQuery {
  	q.restrict = true
  	return q
  }
  
  //------------------------------------------------------------------------------
  
  // Comment adds a comment to the query, wrapped by /* ... */.
  func (q *TruncateTableQuery) Comment(comment string) *TruncateTableQuery {
  	q.comment = comment
  	return q
  }
  
  //------------------------------------------------------------------------------
  
  func (q *TruncateTableQuery) Operation() string {
  	return "TRUNCATE TABLE"
  }
  
  func (q *TruncateTableQuery) AppendQuery(
  	gen schema.QueryGen, b []byte,
  ) (_ []byte, err error) {
  	if q.err != nil {
  		return nil, q.err
  	}
  
  	b = appendComment(b, q.comment)
  
  	if !gen.HasFeature(feature.TableTruncate) {
  		b = append(b, "DELETE FROM "...)
  
  		b, err = q.appendTables(gen, b)
  		if err != nil {
  			return nil, err
  		}
  
  		return b, nil
  	}
  
  	b = append(b, "TRUNCATE TABLE "...)
  
  	b, err = q.appendTables(gen, b)
  	if err != nil {
  		return nil, err
  	}
  
  	if q.db.HasFeature(feature.TableIdentity) {
  		if q.continueIdentity {
  			b = append(b, " CONTINUE IDENTITY"...)
  		} else {
  			b = append(b, " RESTART IDENTITY"...)
  		}
  	}
  
  	b = q.appendCascade(gen, b)
  
  	return b, nil
  }
  
  //------------------------------------------------------------------------------
  
  func (q *TruncateTableQuery) Exec(ctx context.Context, dest ...any) (sql.Result, error) {
  	// if a comment is propagated via the context, use it
  	setCommentFromContext(ctx, q)
  
  	queryBytes, err := q.AppendQuery(q.db.gen, q.db.makeQueryBytes())
  	if err != nil {
  		return nil, err
  	}
  
  	query := internal.String(queryBytes)
  
  	res, err := q.exec(ctx, q, query)
  	if err != nil {
  		return nil, err
  	}
  
  	return res, nil
  }
  