sq/libsq/core/sqlmodel/sqlmodel.go
Neil O'Toole a92b9abf34
Initial work on a JSON driver (#70)
* implementation work for json importers

* json driver checkpoint

* working on json.ParseObjectsInArray

* json.ParseObjectsInArray seems to be working

* checkpoint while tidying up ParseObjectsInArray

* more tidy checkpoint

* more tidy checkpoint 2

* tidying up ParseObjectsInArray

* tidy up

* code/docs cleanup

* more cleanup of json driver

* more cleanup of json driver

* flat json import seemingly working

* improvements to json driver

* json writer now prints empty [] for postgres empty tables
2020-10-20 09:05:43 -06:00

128 lines
3.3 KiB
Go

// Package core.sqlmodel provides functionality for modeling SQL constructs.
package sqlmodel
import (
"strings"
"github.com/neilotoole/sq/libsq/core/errz"
"github.com/neilotoole/sq/libsq/core/kind"
)
// TableDef models a database table definition.
type TableDef struct {
// Name is the table name.
Name string `json:"name"`
// PKColName is the name of the primary key column, or empty.
//
// Deprecated: this construct does not allow for composite PK.
PKColName string `json:"primary_key,omitempty"`
// AutoIncrement, if true, indicates that a PK column
// should autoincrement.
//
// Deprecated: this construct does not allow for composite PK.
AutoIncrement bool `json:"auto_increment"`
// Cols is the table's column definitions.
Cols []*ColDef `json:"cols"`
}
// NewTableDef is a convenience constructor for creating
// a simple table definition.
func NewTableDef(tblName string, colNames []string, colKinds []kind.Kind) *TableDef {
tblDef := &TableDef{Name: tblName}
cols := make([]*ColDef, len(colNames))
for i := range colNames {
cols[i] = &ColDef{Table: tblDef, Name: colNames[i], Kind: colKinds[i]}
}
tblDef.Cols = cols
return tblDef
}
// ColNames returns a new slice containing the names
// of t's columns.
func (t *TableDef) ColNames() []string {
names := make([]string, len(t.Cols))
for i, col := range t.Cols {
names[i] = col.Name
}
return names
}
// ColKinds returns a new slice containing the kinds
// of t's columns.
func (t *TableDef) ColKinds() []kind.Kind {
kinds := make([]kind.Kind, len(t.Cols))
for i, col := range t.Cols {
kinds[i] = col.Kind
}
return kinds
}
func (t *TableDef) String() string {
return t.Name + "(" + strings.Join(t.ColNames(), ",") + ")"
}
// ColsByName returns the ColDefs for each named column, or an error if any column
// is not matched.
func (t *TableDef) ColsByName(cols []string) ([]*ColDef, error) {
defs := make([]*ColDef, len(cols))
for i, name := range cols {
found := false
for _, def := range t.Cols {
if def.Name == name {
defs[i] = def
found = true
break
}
}
if !found {
return nil, errz.Errorf("could not find column definition %q in table %q", name, t.Name)
}
}
return defs, nil
}
// FindCol returns the named ColDef or nil if not found.
func (t *TableDef) FindCol(name string) (*ColDef, error) {
for _, col := range t.Cols {
if col.Name == name {
return col, nil
}
}
return nil, errz.Errorf("could not find column definition %q in table %q", name, t.Name)
}
// ColDef models a table column definition.
type ColDef struct {
Name string `json:"name"`
Table *TableDef `json:"-"`
Kind kind.Kind `json:"kind"`
NotNull bool `json:"not_null"`
HasDefault bool `json:"has_default"`
// Size typically applies to text fields, e.g. VARCHAR(255).
Size int `json:"size"`
Unique bool `json:"unique"`
ForeignKey *FKConstraint `json:"foreign_key,omitempty"`
}
// FKConstraint models a foreign key constraint.
type FKConstraint struct {
// RefTable is the name of the referenced parent table.
RefTable string `json:"ref_table"`
// RefCol is the name of the referenced col in the parent table.
RefCol string `json:"ref_col"`
// OnDelete is one of CASCADE or SET_NULL, defaults to CASCADE.
OnDelete string `json:"on_delete"`
// OnUpdate is one of CASCADE or SET_NULL, defaults to CASCADE.
OnUpdate string `json:"on_update"`
}