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/internal"
  	"github.com/uptrace/bun/schema"
  )
  
  // DropTableQuery builds DROP TABLE statements.
  type DropTableQuery struct {
  	baseQuery
  	cascadeQuery
  
  	ifExists bool
  	comment  string
  }
  
  var _ Query = (*DropTableQuery)(nil)
  
  // NewDropTableQuery returns a DropTableQuery tied to the provided DB.
  func NewDropTableQuery(db *DB) *DropTableQuery {
  	q := &DropTableQuery{
  		baseQuery: baseQuery{
  			db: db,
  		},
  	}
  	return q
  }
  
  func (q *DropTableQuery) Conn(db IConn) *DropTableQuery {
  	q.setConn(db)
  	return q
  }
  
  func (q *DropTableQuery) Model(model any) *DropTableQuery {
  	q.setModel(model)
  	return q
  }
  
  func (q *DropTableQuery) Err(err error) *DropTableQuery {
  	q.setErr(err)
  	return q
  }
  
  //------------------------------------------------------------------------------
  
  func (q *DropTableQuery) Table(tables ...string) *DropTableQuery {
  	for _, table := range tables {
  		q.addTable(schema.UnsafeIdent(table))
  	}
  	return q
  }
  
  func (q *DropTableQuery) TableExpr(query string, args ...any) *DropTableQuery {
  	q.addTable(schema.SafeQuery(query, args))
  	return q
  }
  
  func (q *DropTableQuery) ModelTableExpr(query string, args ...any) *DropTableQuery {
  	q.modelTableName = schema.SafeQuery(query, args)
  	return q
  }
  
  //------------------------------------------------------------------------------
  
  func (q *DropTableQuery) IfExists() *DropTableQuery {
  	q.ifExists = true
  	return q
  }
  
  func (q *DropTableQuery) Cascade() *DropTableQuery {
  	q.cascade = true
  	return q
  }
  
  func (q *DropTableQuery) Restrict() *DropTableQuery {
  	q.restrict = true
  	return q
  }
  
  //------------------------------------------------------------------------------
  
  // Comment adds a comment to the query, wrapped by /* ... */.
  func (q *DropTableQuery) Comment(comment string) *DropTableQuery {
  	q.comment = comment
  	return q
  }
  
  //------------------------------------------------------------------------------
  
  func (q *DropTableQuery) Operation() string {
  	return "DROP TABLE"
  }
  
  func (q *DropTableQuery) AppendQuery(gen schema.QueryGen, b []byte) (_ []byte, err error) {
  	if q.err != nil {
  		return nil, q.err
  	}
  
  	b = appendComment(b, q.comment)
  
  	b = append(b, "DROP TABLE "...)
  	if q.ifExists {
  		b = append(b, "IF EXISTS "...)
  	}
  
  	b, err = q.appendTables(gen, b)
  	if err != nil {
  		return nil, err
  	}
  
  	b = q.appendCascade(gen, b)
  
  	return b, nil
  }
  
  //------------------------------------------------------------------------------
  
  func (q *DropTableQuery) Exec(ctx context.Context, dest ...any) (sql.Result, error) {
  	if q.table != nil {
  		if err := q.beforeDropTableHook(ctx); err != nil {
  			return nil, err
  		}
  	}
  
  	// 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
  	}
  
  	if q.table != nil {
  		if err := q.afterDropTableHook(ctx); err != nil {
  			return nil, err
  		}
  	}
  
  	return res, nil
  }
  
  func (q *DropTableQuery) beforeDropTableHook(ctx context.Context) error {
  	if hook, ok := q.table.ZeroIface.(BeforeDropTableHook); ok {
  		if err := hook.BeforeDropTable(ctx, q); err != nil {
  			return err
  		}
  	}
  	return nil
  }
  
  func (q *DropTableQuery) afterDropTableHook(ctx context.Context) error {
  	if hook, ok := q.table.ZeroIface.(AfterDropTableHook); ok {
  		if err := hook.AfterDropTable(ctx, q); err != nil {
  			return err
  		}
  	}
  	return nil
  }
  
  // String returns the generated SQL query string. The DropTableQuery instance must not be
  // modified during query generation to ensure multiple calls to String() return identical results.
  func (q *DropTableQuery) String() string {
  	buf, err := q.AppendQuery(q.db.QueryGen(), nil)
  	if err != nil {
  		panic(err)
  	}
  	return string(buf)
  }
  