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