support to check if a column is primary key #744
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schema/schema.go
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| func (ta *Table) GetPKColumn(index int) *TableColumn { | ||
| return &ta.Columns[ta.PKColumns[index]] | ||
| } | ||
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| // Get Index by column index. Return nil if the column is not a index. |
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Get Index by column index
What if the column has multiple indexes?
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Yes, I think this function is to get primary index only. PKColumns must be PRIMARY. I Will update.
fungaren
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schema/schema.go
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| func (ta *Table) GetPKColumn(index int) *TableColumn { | ||
| return &ta.Columns[ta.PKColumns[index]] | ||
| } | ||
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| // Get Primary Index by column index. Return nil if the column is not a primary index. | ||
| func (ta *Table) GetPKIndex(colIndex int) *Index { |
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I'm not sure what's your purpose. If you want to get PK, you can add a new field just like Table.PKColumns
Also please change schema_test.go to add a test covering your change
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This function is very useful when you want to check if a column is a primary key. For example, when you get a canal.RowsEvent, and you may want to find out the primary key in the row. However, what we have currently is just Table.PKColumns, which is a slice of column index for the table's primary key.
Line 423 in 0999529
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The usage of this function "Get Primary Index by column index." is very weird, primary key is a property of table, column is a property of table or index, it's strange to do reverse thing. I'm considering to return a bool to indicate if a column is in a primary key, but that's too trivial to add a public function, one line slices.Contains(Table.PKColumns, colIndex) should be enough.
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Yes I agree with that it is enough to return a boolean, named to IsPrimaryKey(). And the existing GetPKColumn() is also weird, haha.
And slices.Contains requires an extra import which is not necessary if you just need this simple function.
I also added unit test for the existing GetPKColumn().
schema/schema.go
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| @@ -183,10 +183,23 @@ func (ta *Table) FindColumn(name string) int { | |||
| return -1 | |||
| } | |||
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| // Get TableColumn by primary index index | |||
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| // Get TableColumn by primary index index | |
| // Get TableColumn by column index of primary key. |
schema/schema.go
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| return &ta.Columns[ta.PKColumns[index]] | ||
| } | ||
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| func (ta *Table) IsPrimaryKey(colIndex int) bool { | ||
| for _, _colIndex := range ta.PKColumns { |
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maybe you can just use i instead of _colIndex, we don't have _xxx stype in other codes.
fungaren
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